A keyed AGC circuit is responsive to the peak level of synchronizing signal components of a composite video signal for generating an AGC control voltage in a television receiver. A peak detector samples the peaks of the synchronizing signal components during keying intervals. Signal translating means are keyed by an AGC keying signal to provide charging and discharging currents for an AGC filter capacitor which are each a function of the signal level stored by the peak detector. A discharge circuit is responsive to the absence of the AGC keying signal to continuously discharge the peak detector during video scanning intervals to prevent the retention of charge by the peak detector resulting from noise or video signal information.