An automatic gain control (AGC) method and system for a radio receiver are proposed in which the ACG comprises two AGC loops; a first loop controlling signal gain in the analogue portion of the radio receiver, a second loop controlling gain in the digital domain after digitization of the received signal. The analogue AGC loop has a slower response time than the digital AGC loop. When applied to a multi-branch diversity receiver, each branch has its own digital AGC loop, but the analogue gain can be common to all branches, based on measurement of the analogue signal in each branch.