A method and system are provided for monitoring adjacent cells in a mobile radio telephone system, in which a mobile station located in a cell of a mobile radio telephone system receives, for purposes of monitoring adjacent cells, transmits signals coded with different cell-specific codes from base stations of adjacent cells and codes and evaluates these in accordance with the respective cell-specific codes, wherein at least the base station currently responsible for the mobile station transmits a signaling information item which informs the mobile station of the codes to be used in the monitoring of adjacent cells and/or of the codes not to be used in monitoring adjacent cells, and the mobile station, in monitoring adjacent cells, only decodes and evaluates the transmit signals of the adjacent cells coded with a code which can be used for the monitoring of adjacent cells in accordance with the signaling information.