Formerly a prophet, he changed himself from a man to a woman, indulging in the pleasures of both.
The blind prophet of Thebes, Tiresias was the son of the nymph Callirrhoe, and was the high priest of Apollo. He had originally been born sighted, but lost the use of his eyes after being blinded by either the goddess Athena (for seeing her naked by accident), or by the queen of the gods, Hera (after he had sided with Zeus against her in an argument). As compensation, he is given the gift of prophecy.
One myth describes his encounter with a pair of mating snakes. By striking them with a stick, Tiresias is magically changed into a woman. She lives life as a wife and mother for a time before finding another pair of mating serpents. Striking again causes Tiresias to revert back to being male.
In the play Oedipus Rex, in order to solve the murder of the former king of Thebes, Laius, and get rid of a plague sent by the gods in retribution, the current king Oedipus calls on Tiresias for advice and insight. Tiresias is reluctant to speak, knowing the truth of the murder, but is goaded into claiming Oedipus is the killer, although Oedipus doesn't know it yet. Tiresias reveals that he knew Oedipus's true parents before he departs, causing Oedipus to begin hunting for his birthparents. The king later finds out that not only had Tiresias been correct in telling him he had killed the former Theban king, but that Laius and Jocasta, (Laius's widow and Oedipus's current wife) were in truth the young king's real parents. Devastated, Oedipus blinds himself with pins and is exiled from Thebes to lift the plague.
Tiresias also appears in the play Antigone. Prior to exile, for their disobedience Oedipus had cursed his sons, Etiocles and Polynices, prophesying that they would one day kill one another. After their father is gone, Oedipus's brother-in-law, Kreon, becomes king and raises the two boys, though he favors Etiocles. Despite an arrangement that Etiocles and Polynices will share the throne of Thebes when they become adults, once Etiocles has the throne he refuses to hand over his power, prompting Polynices to rebel and declare war on the city. As Oedipus predicted, the brothers slay one another in battle. Kreon orders a splendid funeral for Etiocles, but decrees that Polynices and the rebels must be left outside the city to rot, on penalty of death to any who don't obey this order. Horrified, Polynices's sister Antigone buries the body secretly. Kreon has it exhumed and Antigone is caught trying to bury her brother again. Kreon decides to uphold the death penalty and has Antigone buried alive in a cave with a minor amount of food. Tiresias immediately goes to Kreon, and informs him that the gods are furious with his treatment of a dead body (the dead must be given proper funeral rites). Tiresias instructs Kreon to bury Polynices and release Antigone, or the gods will take away those he loves most and curse him for the rest of his life. Kreon immediately buries Polynices, but is too late to free Antigone, who has hanged herself in the cave. His son, Antigone's fiance, kills himself, and upon learning of this, Kreon's wife also commits suicide, cursing her husband with her last breath.
After the death of Tiresias, in Homer's Odyssey, the protagonist Odysseus, king of Ithaca, descends into the Underworld to seek Tiresias's advice, using blood from a sacrificed animal to summon him. The shade informs Odysseus that Poseidon would not forgive him for blinding his son, Polyphemus the Cyclops, and that when he reached the Island of Helios that he must not eat any of the sheep or the cattle on the island (although Eurylochus, Odysseus' cousin, ignored this advice). Tiresias then warned Odysseus about the suitors that were after his wife and his son, Telemachus. Then the old priest told the King of Ithaca that he must journey to a land where no mortal has gone before. When the inhabitants of the land called Odysseus' oar a "winnowing shovel" Tiresias instructed him to place it in the ground as a sacrifice to appease Poseidon. Then, and only then would he return to Ithaca.
- In The Inferno, Dante and Virgil behold the shade of Tiresias in the fourth pit of the Malebolge, damned for his prophetic acts.