The October 1503 papal conclave elected Cardinal Giuliano della Rovere as Pope Julius II to succeed Pope Pius III. The conclave took place during the Italian Wars barely a month after the papal conclave, September 1503, and none of the electors had travelled far enough from Rome to miss the conclave. The number of participating cardinals was thirty-eight, the College of Cardinals having been reduced by the election of Piccolomini as Pius III, who did not elevate cardinals. At a consistory on 11 October Pope Pius had proposed to make Cardinal d'Amboise's nephew a cardinal, as part of his effort to conciliate the French, but the response from the cardinals was not enthusiastic.

The September 1503 papal conclave elected Pope Pius III to succeed Pope Alexander VI. Due to the Italian Wars, the College of Cardinals was surrounded by three potentially hostile armies, loyal to Louis XII of France, Ferdinand II of Aragon, and Cesare Borgia.