Offer a two unit salat at any time preferably near the time of noon for it was at that hour that the event of Ghadeer took place.
In the first Rakat recite Sura Qadr after Sura Fatihah and in the second Rakat recite Sura Ikhlaas after Sura Fatiha
It is reported that those who perform this observance recieve the reward of someone who had been present on the day of Ghadeer with the Holy Prophet (peace and blessings be on him and his family) and sworn allegiance to him, as regards to the divinely commissioned leadership (wilayah) of Imam `Ali (peace be upon him).

شُكْراً لِلَّهِ

shukran lillah

Thanks be to Allah.

After salat, one should prostrate say one hundred times

اَللَّهُمَّ إِنِّي أَسْأَلُكَ بِأَنَّ لَكَ ٱلْحَمْدَ

allahumma inni as'aluka bi'anna laka alhamda

O Allah, I beseech You in the name of that all praise be to You,

Then say the following dua:

وَحْدَكَ لاَ شَرِيكَ لَكَ

wahdaka la sharika laka

alone, without having any partner,

وَأَنَّكَ وَاحِدٌ أَحَدٌ صَمَدٌ

wa annaka wahidun ahadun samadun

and that You are One, One and Only, and eternally Besought of all;

لَمْ تَلِدْ وَلَمْ تُولَدْ

lam talid wa lam tulad

You beget not nor are You begotten,

وَلَمْ يَكُنْ لَكَ كُفُواً أَحَدٌ

wa lam yakun laka kufwan ahadun

and there is none like You;

وَأَنَّ مُحَمَّداً عَبْدُكَ وَرَسُولُكَ

wa anna muhammadan `abduka wa rasuluka

and that Muhammad is Your servant and Messenger,

صَلَوَاتُكَ عَلَيْهِ وَآلِهِ

salawatuka `alayhi wa alihi

Your blessings be upon him and his Household.

يَا مَنْ هُوَ كُلَّ يَوْمٍ فِي شَأْنٍ

ya man huwa kulla yawmin fi sha'nin

O He Who is in a state every day!

كَمَا كَانَ مِنْ شَأْنِكَ أَنْ تَفَضَّلْتَ عَلَيَّ

kama kana min sha'nika an tafaddalta `alayya

Just as You decided to confer upon me with Your favor

بِأَنْ جَعَلْتَنِي مِنْ أَهْلِ إِجَابَتِكَ

bi'an ja`altani min ahli ijabatika

when You included me with those to whom You responded,

وَأَهْلِ دِينِكَ

wa ahli dinika

the company of Your religion,

وَأَهْلِ دَعْوَتِكَ

wa ahli da`watika

and the company of those who pray You,

وَوَفَّقْتَنِي لِذٰلِكَ فِي مُبْتَدَءِ خَلْقِي

wa waffaqtani lidhalika fi mubtada'i khalqi

You had led me to this in the beginning of Your creation of me

تَفَضُّلاً مِنْكَ وَكَرَماً وَجُوداً

tafaddulan minka wa karaman wa judan

as a sign of Your favoring, generosity, and magnanimity.

ثُمَّ أَرْدَفْتَ ٱلْفَضْلَ فَضْلاًَ

thumma ardafta alfadla fadlan

Then, You followed the favor with another favor,

وَٱلْجُودَ جُوداً

waljuda judan

the magnanimity with another magnanimity,

وَٱلْكَرَمَ كَرَماً

walkarama karaman

and the generosity with another generosity,

رَأْفَةً مِنْكَ وَرَحْمَةً

ra'fatan minka wa rahmatan

on account of Your kindness and mercy,

إِلَىٰ أَنْ جَدَّدْتَ ذٰلِكَ ٱلْعَهْدَ لِي تَجْدِيداً

ila an jaddadta dhalika al`ahda li tajdidan

so You renewed all that for me over again

بَعْدَ تَجدِيدِكَ خَلْقِي

ba`da tajdidika khalqi

after You renewed my creation

وَكُنْتُ نَسْياً مَنْسِيّاً

wa kuntu nasyan mansiyyan

while I was a thing quite forgotten,

نَاسِياً سَاهِياً غَافِلاً

nasiyan sahiyan ghafilan

oblivious, unmindful, and heedless.

فَأَتْمَمْتَ نِعْمَتَكَ

fa'atmamta ni`mataka

So, You completed Your grace

بِأَنْ ذَكَّرْتَنِي ذٰلِكَ

bi'an dhakkartani dhalika

when You made me remember that,

وَمَنَنْتَ بِهِ عَلَيَّ

wa mananta bihi `alayya

bestowed this favor upon me,

وَهَدَيْتَنِي لَهُ

wa hadaytani lahu

and guided me to it.

فَليَكُنْ مِنْ شَأْنِكَ

falyakun min sha'nika

So, (please) may one of Your decisions,

يَا إِلٰهِي وَسَيِّدِي وَمَولاَيَ

ya ilahi wa sayyidi wa mawlaya

O my God, Master, and Sustainer,

أَنْ تُتِمَّ لِي ذٰلِكَ وَلاَ تَسْلُبْنيهِ

an tutimma li dhalika wa la taslubnihi

be that You perfect this for me and never deprive me of it

حَتَّىٰ تَتَوَفَّانِي عَلَىٰ ذٰلِكَ

hatta tatawaffani `ala dhalika

until You cause me to die on this faith

وَأَنْتَ عَنِّي رَاضٍ

wa anta `anni radin

and You are pleased with me.

فَإِنَّكَ أَحَقُّ ٱلْمُنعِمِينَ

fa'innaka ahaqqu almun`imina

For, verily, You are the worthiest Benefactor

أَنْ تُتِمَّ نِعْمَتَكَ عَلَيَّ

an tutimma ni`mataka `alayya

of perfecting Your grace for me.

اَللَّهُمَّ سَمِعْنَا وَأَطَعْنَا

allahumma sami`na wa ata`na

O Allah, we have listened, obeyed,

وَأَجَبْنَا دَاعِيَكَ بِمَنِّكَ

wa ajabna da`iyaka bimannika

and answered Your call on account of Your favor to us.

فَلَكَ ٱلْحَمْدُ

falaka alhamdu

So, all praise be to You.

غُفْرَانَكَ رَبَّنَا

ghufranaka rabbana

Your forgiveness, O our Lord, we seek

وَإِلَيْكَ ٱلْمَصِيرُ

wa ilayka almasiru

and to You is the return.

آمَنَّا بِٱللَّهِ وَحْدَهُ

amanna billahi wahdahu

We believe in Allah, alone;

لاَ شَرِيكَ لَهُ

la sharika lahu

there is no partner with Him,

وَبِرَسُولِهِ مُحَمَّدٍ

wa birasulihi muhammadin

and (we believe) in His Messenger, Muhammad,

صَلَّىٰ ٱللَّهُ عَلَيْهِ وَآلِهِ

salla allahu `alayhi wa alihi

may Allah’s blessings be upon him and his Household,

وَصَدَّقْنَا وَأَجَبْنَا دَاعِيَ ٱللَّهِ

wa saddaqna wa ajabna da`iya allahi

we trust and respond to the caller of Allah,

وَٱتَّبَعْنَا الرَّسُولَ فِي مُوَالاَةِ مَوْلاَنَا

wattaba`na alrrasula fi muwalati mawlana

we followed the Messenger as regards the loyalty to our master,

وَمَوْلَىٰ ٱلْمُؤْمِنِينَ

wa mawla almu'minina

and the master of the believers,

أَمِيرِ ٱلْمُؤْمِنِينَ

amiri almu'minina

the commander of the believers,

عَلِيِّ بْنِ أَبِي طَالِبٍ

`aliyyi bni abi talibin

`Ali, the son of Abu-Talib,

عَبْدِ ٱللَّهِ وَأَخِي رَسُولِهِ

`abdi allahi wa akhi rasulihi

Allah’s servant and His Messenger’s brother,

وَٱلصِّدِّيقِ ٱلأَكْبَرِ

walssiddiqi al'akbari

the grandest veracious,

وَٱلْحُجَّةِ عَلَىٰ بَرِيَّتِهِ

walhujjati `ala bariyyatihi

the claim on His creation,

ٱلْمُؤَيِّدِ بِهِ نَبِيَّهُ

almu'ayyidi bihi nabiyyahu

by him, He supported His Prophet

وَدِينَهُ ٱلْحَقَّ ٱلْمُبِينَ

wa dinahu alhaqqa almubina

and His religion, the manifest true.

عَلَماً لِدِينِ ٱللَّهِ

`alaman lidini allahi

(We believe in him as) the sign of Allah’s religion,

وَخَازِناً لِعِلْمِهِ

wa khazinan li`ilmihi

the keeper of His knowledge,

وَعَيْبَةَ غَيْبِ ٱللَّهِ

wa `aybata ghaybi allahi

the container of Allah’s unseen affairs,

وَمَوْضِعَ سِرِّ ٱللَّهِ

wa mawdi`a sirri allahi

the carrier of Allah’s secrets,

وَأَمِينَ ٱللَّهِ عَلَىٰ خَلْقِهِ

wa amina allahi `ala khalqihi

the trustee of Allah on His creatures,

وَشَاهِدَهُ فِي بَرِيَّتِهِ

wa shahidahu fi bariyyatihi

and His witness on His created beings.

اَللَّهُمَّ رَبَّنَا إِنَّنَا سَمِعْنَا مُنَادِياً

allahumma rabbana innana sami`na munadiyan

O Allah, O our Lord, surely, we have heard a preacher

يُنَادِي لِلإِيـمَانِ أَنْ آمِنُوٱ بِرَبِّكُمْ فَآمَنَّا

yunadi lil'imani an aminu birabbikum fa'amanna

calling to the faith, saying, “Believe in your Lord.” So, we did believe.

رَبَّنَا فَٱغْفِرْ لَنَا ذُنُوبَنَا

rabbana faghfir lana dhunubana

Our Lord! Forgive us therefore our faults,

وَكَفِّرْ عَنَّا سَيِّئَاتِنَا

wa kaffir `anna sayyi'atina

cover our evil deeds,

وَتَوَفَّنَا مَعَ ٱلأَبْرَارِ

wa tawaffana ma`a al'abrari

and make us die with the righteous ones.

رَبَّنَا وَآتِنَا مَا وَعَدْتَنَا عَلَىٰ رُسُلِكَ

rabbana wa atina ma wa`adtana `ala rusulika

Our Lord! And grant us what You have promised us by Your messengers;

وَلاَ تُخْزِنَا يَوْمَ ٱلْقِيَامَةِ

wa la tukhzina yawma alqiyamati

and disgrace us not on the Day of Resurrection.

إِنَّكَ لاَ تُخْلِفُ ٱلْمِيعَادَ

innaka la tukhlifu almi`ada

Surely, You do not fail to perform the promise.

فَإِنَّا يَا رَبَّنَا بِمَنِّكَ وَلُطْفِكَ

fa'inna ya rabbana bimannika wa lutfika

Because we, O our Lord, on account of Your grace and kindness,

أَجَبْنَا دَاعِيَكَ

ajabna da`iyaka

responded to Your caller

وَٱتَّبَعْنَا ٱلرَّسُولَ وَصَدَّقْنَاهُ

wattaba`na alrrasula wa saddaqnahu

followed the Messenger, believed him,

وَصَدَّقْنَا مَوْلَىٰ ٱلْمُؤْمِنِينَ

wa saddqna mawla almu'minina

trusted the Master of the Believers,

وَكَفَرْنَا بِٱلْجِبْتِ وَٱلطَّاغُوتِ

wa kafarna biljibti walttaghuti

and denied the idols (Jibt) and false deities (Taghut).

فَوَلِّنَا مَا تَوَلَّيْنَا

fawallina ma tawallayna

So, (please) join us with those whom we chose to join

وَٱحْشُرْنَا مَعَ أَئِمَّتِنَا

wahshurna ma`a a'immatina

and put us in the group of our Imams,

فَإِنَّا بِهِمْ مُؤْمِنُونَ مُوقِنُونَ

fa'inna bihim mu'minuna muqinuna

for we do believe in them with absolute belief,

وَلَهُمْ مُسَلِّمُونَ

wa lahum musallimuna

and to them we do submit.

آمَنَّا بِسِرِّهِمْ وَعَلاَنِيَتِهِمْ

amanna bisirrihim wa `alaniyatihim

We believe in their secret and open affairs,

وَشَاهِدِهِمْ وَغَائِبِهِمْ

wa shahidihim wa gha'ibihim

their present and their absent ones,

وَحَيِّهِمْ وَمَيِّتِهِمْ

wa hayyihim wa mayyitihim

and their living and their dead ones.

وَرَضِينَا بِهِمْ أَئِمَّةً

wa radina bihim a'immatan

We consent to them as our imams,

وَقَادَةً وَسَادَةً

wa qadatan wa sadatan

leaders, and chiefs.

وَحَسْبُنَا بِهِمْ

wa hasbuna bihim

And we stop at them

بَيْنَنَا وَبَيْنَ ٱللَّهِ دُونَ خَلْقِهِ

baynana wa bayna allahi duna khalqihi

in all of our affairs with Allah, excluding all other creatures of Him.

لاَ نَبْتَغِي بِهِمْ بَدَلاً

la nabtaghi bihim badalan

We do not seek any substitutes of them,

وَلاَ نَتَّخِذُ مِنْ دُونِهِمْ وَلِيجَةً

wa la nattakhidhu min dunihim walijatan

and we do not betake ourselves any friends other than them.

وَبَرِئْنَا إِلَىٰ ٱللَّهِ

wa bari'na ila allahi

We, before Allah, disapprove

مِنْ كُلِّ مَنْ نَصَبَ لَهُمْ حَرْباً

min kulli man nasaba lahum harban

all those who made war with them,

مِنَ ٱلْجِنِّ وَٱلإِنْسِ

min aljinn wal'insi

from jinn and men,

مِنَ ٱلأَوَّلِينَ وَٱلآخِرِينَ

min al'awwalina wal'akhirina

from the past and the coming generations.

وَكَفَرْنَا بِٱلْجِبْتِ وَٱلطَّاغُوتِ

wa kafarna biljibti walttaghuti

We deny the idols, the false deities,

وَٱلأَوْثَانِ ٱلأَرْبَعَةِ

wal-awthani al'arba`ati

the four pagans,

وَأَشْيَاعِهِمْ وَأَتْبَاعِهِمْ

wa ashya`ihim wa atba`ihim

their partisans, their followers,

وَكُلِّ مَنْ وَالاَهُمْ

wa kulli man walahum

and all those who support them

مِنَ ٱلْجِنِّ وَٱلإِنْسِ

min aljinni wal'insi

from jinn and human beings

مِنْ أَوَّلِ ٱلدَّهْرِ إِلَىٰ آخِرِهِ

min awwali alddahri ila akhirihi

from the first of time to the last of it.

اَللَّهُمَّ إِنَّا نُشْهِدُكَ

allahumma inna nushhiduka

O Allah, we call You to witness

أَنَّا نَدِينُ بِمَا دَانَ بِهِ مُحَمَّدٌ وَآلُ مُحَمَّدٍ

annaa nadinu bima dana bihi muhammadun wa alu muhammadin

that we profess all that professed by Muhammad and the Household of Muhammad,

صَلَّىٰ ٱللَّهُ عَلَيْهِ وَعَلَيْهِمْ

salla allahu `alayhi wa `alayhim

Allah’s blessings be upon him and them.

وَقَوْلُنَا مَا قَالُوٱ

wa qawluna ma qalwa

We say only that which they say

وَدِينُنَا مَا دَانُوٱ بِهِ

wa dinuna ma danu bihi

and we believe in only that in which they believe.

مَا قَالُوٱ بِهِ قُلْنَا

ma qalu bihi qulna

What they say is our saying,

وَمَا دَانُوٱ بِهِ دِنَّا

wa ma danu bihi dinna

what they profess is what we profess,

وَمَا أَنْكَرُوٱ أَنْكَرْنَا

wa ma ankaru ankarna

what they reject is what we reject,

وَمَنْ وَالَوْٱ وَالَيْنَا

wa man walaw walayna

those to whom they adhere are they to whom we adhere,

وَمَنْ عَادَوْٱ عَادَيْنَا

wa man `adaw `adayna

those whom they oppose are they whom we oppose,

وَمَنْ لَعَنُوٱ لَعَنَّا

wa man la`anu la`anna

those whom they curse are they whom we curse,

وَمَنْ تَبَرَّؤُٱ مِنهُ تَبَرَّأْنَا مِنْهُ

wa man tabarra'u minhu tabarra'na minhu

those whom they condemn are they whom we condemn,

وَمَنْ تَرَحَّمُوٱ عَلَيْهِ تَرَحَّمْنَا عَلَيْهِ

wa man tarahhamu `alayhi tarahhamna `alayhi

and those to whom they pray for mercy are they to whom we pray for mercy.

آمَنَّا وَسَلَّمْنَا

amanna wa sallamna

We believe in, submit to,

وَرَضِينَا وَٱتَّبَعْنَا مَوَالِيَنَا

wa radina wattaba`na mawaliyana

accept, and follow our masters,

صَلَوَاتُ ٱللَّهِ عَلَيْهِمْ

salawatu allahi `alayhim

Allah’s blessings be upon them.

اَللَّهُمَّ فَتِمِّمْ لَنَا ذٰلِكَ وَلاَ تَسْلُبْنَاهُ

allahumma fatammim lana dhalika wa la taslubnahu

O Allah, so, perfect this for us and do not deprive us of it.

وَٱجْعَلْهُ مُسْتَقِرّاً ثَابِتاً عِنْدَنَا

waj`alhu mustaqirran thabitan `indana

Make it well-established and fixed with us

وَلاَ تَجْعَلْهُ مُسْتَعَاراً

wa la taj`alhu musta`aran

and do not make it temporal (belief).

وَأَحْيِنَا مَا أَحْيَيْتَنَا عَلَيْهِ

wa ahyina ma ahyaytana `alayhi

Make us live on it (no matter how long You will make us to live)

وَأَمِتْنَا إِذَا أَمَتَّنَا عَلَيْهِ

wa amitna idha amattana `alayhi

and cause us to die on it (when You decide to terminate our lives).

آلُ مُحَمَّدٍ أَئِمَّتُنَا

alu muhammadin a'immatuna

Muhammad’s Household are our Imams;

فَبِهِمْ نَأْتَمُّ

fabihim na'tammu

so, we follow them

وَإِيَّاهُمْ نُوَالِي

wa iyyahum nuwali

and act loyally to them.

وَعَدُوَّهُمْ عَدُوَّ ٱللَّهِ نُعَادِي

wa `aduwwahum `aduwwa allahi nu`adi

We oppose their enemy, the enemy of Allah;

فَٱجْعَلْنَا مَعَهُمْ فِي ٱلدُّنْيَا وَٱلآخِرَةِ

faj`alna ma`ahum fi alddunya wal'akhirati

so, (please) include us with them in this world and the Hereafter,

وَمِنَ ٱلْمُقَرَّبِينَ

wa min almuqarrabina

and make us of those drawn near (to You),

فَإِنَّا بِذٰلِكَ رَاضُونَ

fa'inna bidhalika raduna

for we are satisfied with that.

يَا أَرْحَمَ ٱلرَّاحِمينَ

ya arhama alrrahimina

O most Merciful of all those who show mercy!

اَلْحَمْدُ لِلَّهِ

alhamdu lillahi

All praise be to Allah.

One may then prostrate oneself again and repeat each of the following statements one hundred times:

شُكْراً لِلَّهِ

shukran lillahi

Thanks be to Allah.