During a papal conclave, the cardinals sleep at the Domus Sanctae Marthae, a hotel-like residence in the Vatican City built in 1996 specifically to house them during the conclave. This building has 131 rooms, including 105 two-room suites and 26 single rooms, each with a private bathroom. The residence also features dining rooms, sitting rooms, and chapels. The cardinals are assigned rooms by lot, and the building is secured and off-limits to unauthorized persons during the conclave to maintain secrecy. The cardinals travel daily by bus from Domus Sanctae Marthae to the Sistine Chapel for voting sessions

. Before the Domus Sanctae Marthae was built, cardinals slept on cots in small rooms adjacent to the Sistine Chapel, which were less comfortable and lacked privacy

. The Domus provides a more comfortable and private environment while still maintaining the strict seclusion required for the conclave

. In cases where the number of cardinal electors exceeds the number of rooms available, additional accommodations in nearby Vatican buildings such as the "Old Santa Marta" or other Vatican-owned apartments are used