Method for replacing a used bearing with a new bearing, in particular for replacing a large bearing such as the main bearing of a wind power plant, wherein - the used bearing supports a rotor shaft and is arranged in a used bearing housing, which is fastened to a machine carrier, wherein the machine carrier has a half-shell-like configuration with a recess, into which the bearing housing and the bearing immerse and wherein the bearing housing laterally supports itself on an edge of the machine carrier with radially projecting fastening legs, - the used bearing and the used bearing housing are removed, - the new bearing is divided into bearing ring segments in the circumferential direction and the bearing ring segments are fitted around the rotor shaft and subsequently connected to one another, - a bearing housing is provided for the new bearing, - the bearing housing has fastening flanges for fastening on the machine carrier and is subdivided in the circumferential direction into at least one first housing segment and at least one second housing segment, - wherein the two housing segments (10A, B) are fitted around the rotor shaft and around the bearing without disassembly of the rotor shaft, wherein - at least the first housing segment is rotated around the rotor shaft for assembly, in particular is rotated into the machine carrier and subsequently is connected to the second housing segment, or - at least the first housing segment in a direction perpendicular to the rotor shaft is guided laterally past the latter and subsequently, if necessary, is offset radially in the direction of the rotor shaft and is connected to the second housing segment, and wherein furthermore - at maximum one radially projecting fastening leg is arranged at least on the first housing segment, via which a fastening to the machine carrier is effected. - the used bearing supports a rotor shaft and is arranged in a used bearing housing, which is fastened to a machine carrier, wherein the machine carrier has a half-shell-like configuration with a recess, into which the bearing housing and the bearing immerse and wherein the bearing housing laterally supports itself on an edge of the machine carrier with radially projecting fastening legs, - the used bearing and the used bearing housing are removed, - the new bearing is divided into bearing ring segments in the circumferential direction and the bearing ring segments are fitted around the rotor shaft and subsequently connected to one another, - a bearing housing is provided for the new bearing, - the bearing housing has fastening flanges for fastening on the machine carrier and is subdivided in the circumferential direction into at least one first housing segment and at least one second housing segment, - wherein the two housing segments (10A, B) are fitted around the rotor shaft and around the bearing without disassembly of the rotor shaft, wherein - at least the first housing segment is rotated around the rotor shaft for assembly, in particular is rotated into the machine carrier and subsequently is connected to the second housing segment, or - at least the first housing segment in a direction perpendicular to the rotor shaft is guided laterally past the latter and subsequently, if necessary, is offset radially in the direction of the rotor shaft and is connected to the second housing segment, and wherein furthermore - at maximum one radially projecting fastening leg is arranged at least on the first housing segment, via which a fastening to the machine carrier is effected.