The Aditya Hridayam Hymn is part of the Yuddha Kanda of Valmiki Ramayana (the chapter of war) and contains 31 slokas.

tato yuddha parishrantam samare chintaya sthitam |
ravanam chagrato drishtva yuddhaya samupasthitam || 1

daiva taishcha samagamya drashtu mabhya gato ranam |
upagamya bravidramam agastyo bhagavan rishihi || 2

rama rama mahabaho shrinu guhyam sanatanam |
yena sarvanarin vatsa samare vijayishyasi || 3

aditya-hridayam punyam sarva shatru-vinashanam |
jayavaham japen-nityam akshayyam paramam shivam || 4

sarvamangala-mangalyam sarva papa pranashanam |
chintashoka-prashamanam ayurvardhana-muttamam || 5

rashmi mantam samudyantam devasura-namaskritam |
pujayasva vivasvantam bhaskaram bhuvaneshvaram || 6

sarva devatmako hyesha tejasvi rashmi-bhavanah |
esha devasura gananlokan pati gabhastibhih || 7

esha brahma cha vishnush cha shivah skandah prajapatihi |
mahendro dhanadah kalo yamah somo hyapam patihi || 8

pitaro vasavah sadhya hyashvinau maruto manuh |
vayurvahnih praja-prana ritukarta prabhakarah || 9

adityah savita suryah khagah pusha gabhastiman |
suvarnasadrisho bhanur-hiranyareta divakarah || 10

haridashvah sahasrarchih saptasapti-marichiman |
timironmathanah shambhu-stvashta martanda amshuman || 11

hiranyagarbhah shishira stapano bhaskaro ravihi |
agni garbho’diteh putrah shankhah shishira nashanaha || 12

vyomanathastamobhedi rigyajussamaparagaha |
ghanavrishtirapam mitro vindhya-vithiplavangamaha || 13

atapi mandali mrityuh pingalah sarvatapanaha |
kavirvishvo mahatejah raktah sarva bhavodbhavaha || 14

nakshatra grahataranam-adhipo vishva-bhavanah |
tejasamapi tejasvi dvadashatman namo’stu te || 15

namah purvaya giraye pashchimayadraye namah|
jyotirgananam pataye dinaadhipataye namah || 16

Jayaya jaya bhadraya haryashvaya namo namah |
namo namah sahasramsho adityaya namo namah || 17

nama ugraya viraya sarangaya namo namah |
namah padma prabodhaya martandaya namo namah || 18

brahmeshanachyuteshaya suryayadityavarchase |
bhasvate sarva bhakshaya raudraya vapushe namaha || 19

tamoghnaya himaghnaya shatrughnayamitatmane |
kritaghnaghnaya devaya jyotisham pataye namaha || 20

taptacami karabhaya vahnaye vishvakarmane |
namastamo’bhinighnaya ravaye (rucaye) lokasakshine || 21

nashayat yesha vai bhutam tadeva srijati prabhuh|
payatyesha tapatyesha varshatyesha gabhastibhih || 22

esha supteshu jagarti bhuteshu parinishthitaha |
esha evagnihotram cha phalam chaivagnihotrinam || 23

vedashcha kratavashcaiva kratunam phalam eva cha |
yani krityani lokeshu sarva esha ravih prabhuh || 24

ena-mapatsu krichchreshu kantareshu bhayeshu cha |
kirtayan purushah kashchinnavasidati raghava || 25

pujayasvaina-mekagro devadevam jagatpatim |
etat trigunitam japtva yuddheshu vijayishyasi || 26

asmin kshane mahabaho ravanam tvam vadhishyasi |
evamuktva tada’gastyo jagama cha yathagatam || 27

etachchrutva mahateja nashtashoko’bhavattada |
dharayamasa suprito raghavah prayatatmavan || 28

adityam prekshya japtva tu param harshamavaptavan |
trirachamya shuchirbhutva dhanuradaya viryavan || 29

ravanam prekshya hrishtatma yuddhaya samupagamat |
sarvayatnena mahata vadhe tasya dhrito’bhavat || 30

atha ravi-ravadan-nirikshya ramam
mudita manah paramam prahrishyamanaha |
nishicharapati-sankshayam viditva
suragana-madhyagato vachastvareti || 31

Meaning Of Aditya Hridayam Slokas

1 and 2.  Beholding Sri Rama, standing absorbed in deep thought on the battle-field, exhausted by the fight and facing Ravana who was duly         prepared for the war, the glorious sage Agastya, who had come in the company of gods to witness the encounter (battle) now spoke to Rama as follows:

3. ‘O Rama’, ‘O Mighty armed elegant Rama’, listen carefully to the eternal secret by which, ‘O my child’, you shall conquer all your enemies on the battle field and win against your adversaries.
4. By Chanting the Aditya-Hridayam (the meditation of Sun in the heart ) which is very auspicious and highly beneficial, you will be victorious in battle. This holy hymn dedicated to the Sun-God will result in destroying all enemies and bring you victory and permanent happiness.
5. This supreme prayer is the best amongst auspicious verses, it will destroy all sins, dispel all doubts, alleviate worry and sorrow, anxiety and anguish, and increase the longevity of life. It is a guarantee of complete prosperity.
6. Worship the sun-god, the ruler of the worlds and lord of the universe, who is crowned with effulgent rays, who appears at the horizon and brings light, who is revered by the denizens of heaven (devas) and asuras alike.
7. Indeed, He is the very embodiment of all Gods. He is self-luminous and sustains all with his rays. He nourishes and energizes the inhabitants of all the worlds as well as the host of Gods and demons by his Rays.
8. He is Brahma (the creator), Visnu (the Sustainer), Shiva (the destroyer), Skanda (the son of Siva), Prajapati (progenitor of human race), the mighty Indra (king of heaven), Kubera (the god of wealth and lord of riches), Kala (eternal time), Yama (the Lord of death), Soma (the moon god that nourishes), and Varuna (the lord of sea and ocean).
9. Indeed, he is Pitris (ancestors, manes), the eight Vasus, the Sadhyas, the twin Aswins (physicians of Gods), the Maruts, the Manu, Vayu (the wind God), Agni (the fire God), Prana (the Life breath of all beings), the maker of six seasons and the giver of light.
10. He is the Son of Aditi (the mother of creation), the Sun God who transverser the heavens, he is of brilliant golden color, the possessor of a myriad rays, by illuminating all directions he is the maker of daylight. He is the all pervading, shining principle, the dispeller of darkness, exhibiting beautiful sight with golden hue
11. He has seven horses yoked to his Chariot, shines with brilliant light having infinite rays, is the destroyer of darkness, the giver of happiness and prosperity, mitigator of the sufferings and is the infuser of life. He is the Omnipresent One who pervades all with immeasurable amount of rays.
12. He is Hiranyagarbha born of Aditi of a golden womb, He is Sisirastapana the destroyer of the cold, snow and fog, illuminator, Ravi, bearer of the fire and conch, He is the remover of ignorance and giver of fame.
13. He is the Lord of the firmament and ruler of the sky, remover of darkness. the master of the three vedas Rig, Yaju, Sama, he is a friend of the waters (Varuna) and causes abundant rain. He swiftly courses in the direction South of Vindhya-mountains and sports in the Brahma Nadi.

* The Sun evaporates water from the ocean and rain is produced. Sun is the cause of rain. * The southward (apparent) jouney of the sun causes the change of seasons which is essential for life on earth.

14. He, whose form is circular and is colored in yellow and red hues, is intensely brilliant and enegetic. He is a giver of heat, the cause of all work, of life and death. He is the destroyer of all and is the Omniscient one sustaining the universe and all action.
15. He is the lord of the constellations, stars and planets and the origin of every thing in the universe. Salutations to Aditya who appears in twelve forms (in the shape of twelve months of the year) and whose glory is described in his twelve names.
16. Salutations to the Lord of sunrise and sunset, who rises at the eastern mountains and sets in the western mountains. Salutations to the Lord of the Stellar bodies and to the Lord of daylight.
17. Oh! Lord of thousand rays, son of Aditi, Salutations to you, the bestower of victory, auspiciousness and prosperity, Salutations to the one who has coloured horses to carry him.
18. Salutations to Martandaya the son of Mrukanda Maharisi, the terrible and fierce one, the mighty hero, the one that travels fast. Salutations to the one whose appearance makes the lotus blossom (also the awakener of the lotus in the heart)
19. Salutations to the Lord of Brahma, Shiva and Vishnu, salutations to Surya the sun god, who (by his power and effulgence) is both the illuminator and devourer of all and is of a form that is fierce like Rudra.
20. Salutations to the dispeller of darkness, the destroyer of cold, fog and snow, the exterminator of foes; the one whose extent is immeasurable. Salutations also to the annihilator of the ungrateful and to the Lord of all the stellar bodies, who is the first amongst all the lights of the Universe.
21. Salutations to the Lord shining like molten gold, destroying darkness, who is the transcendental fire of supreme knowledge, who destroys the darkness of ignorance, and who is the cosmic witness of all merits and demerits of the denizens who inhabit the universe. Salutations to Vishvakarma the architect of the universe, the cause of all activity and creation in the world.
22. Salutations to the Lord who creates heat by his brilliant rays. He alone creates, sustains and destroys all that has come into being. Salutations to Him who by His rays consumes the waters, heats them up and sends them down as rain again.
23. Salutations to the Lord who abides in the heart of all beings keeping awake when they are asleep. Verily he is the Agnihotra , the sacrificial fire and the fruit gained by the worshipper of the agnihotra.
24. The Sun God (Ravi) is the origin and protector of the four Vedas (Rig, Yajur, Sama, and Atharva), the sacrifices mentioned in them and the fruits obtained by performing the sacrifices. He is the Lord of all action in this universe and decides the Universal path.
25. Listen Oh Rama! Oh Ragava, scion of the Raghu dynasty, any person, singing the glories of Surya in great difficulties, during affliction, while lost in the wilderness, and when beset with fear, will not come to grief (or loose heart).
26. If you worship this lord of the universe, the God of all Gods, with concentrated mind and devotion by reciting this hymn (Aditya-Hridayam) thrice, you will emerge victorious in the battle.
27. O mighty armed one, you shall truimph over Ravana this very moment. After blessing Lord Rama thus, and predicting that He would slay (the demon) Ravana, sage Agastya took leave and returned to his original place.
28. Having heard this, that great warrior Raghava, feeling greatly delighted, became free from grief. His clouds of worry thus dispelled, the lustrous Lord Rama obeyed the sayings of sage Agastya with great happiness.With composed mind he retained this hymn in his memory, ready to chant the Aditya-Hridayam.
29. Having performed Achamanam (sipping water thice) and being purified, Rama gazing at the sun with devotion, recited the hymn Aditya-Hridayam thrice, then that great hero Raghava was thrilled and lifted his bow.
30. Lord Rama thus cheered, seeing Ravana coming to fight, put forth all his effort with a determination to kill him. (Ravana)
31. Then knowing that the destruction of Ravana was near, the Sun-God Aditya, surrounded by all the Gods in heaven, looked at Rama with delighted mind and exclaimed ‘Hurry up’ – ‘Be quick’.

To read the significance and procedure to Chant the Adiya hridayam click here