The Gathas - the most archaic part of the sacred book of Zoroastrianism "Avesta" - are hymns, the authorship of which is attributed by tradition to the prophet Zarathushtra (the turn of the 2nd and 1st millennia BC). Hymns were read during services during the preparation and sacrifice of haoma, a sacred Zoroastrian plant and drink, and were a central part of the Zoroastrian rite. The Gathas set forth the religious teachings of Zoroaster, the worship of the supreme god Ahura Mazda, his characteristic Holy Spirit (Spenta Mainyu) and other ahuras, emanations of Ahura Mazda. The separation of the world of Truth (Asha), order, harmony, commanded by Ahura Mazda, and the world of Falsehood (Friend), chaos, ruled by the Evil Spirit (Angra Mainyu), is affirmed. A person must make a choice between good and evil. The doctrine is presented about three eras of human history, the coming of the Savior, Judgment by fire and molten metal, the bodily resurrection of the dead, the punishment of sinners, hell and heaven. Let us formulate the main Zoroastrian triad “good thought, good word, good deed.” This publication is the first complete systematic translation of Zarathushtra’s sermons in Russian. Provided with scientific commentary and richly illustrated.