An engine braking control system for automotive automatic transmissions, comprises shift solenoids activated for executing a down-shift operation by selectively engaging or releasing frictional elements of a gear train, in response to engine braking requirements, sensors for monitoring a vehicle speed, an opening angle of a throttle valve, a depression amount of a brake-pedal, and a controller for controlling the down-shift operation on the basis of the signals from the sensors. The controller activates the shift solenoids for executing the down-shift operation only when the throttle opening angle is equal to or less than a predetermined threshold throttle opening angle, the brake-pedal depression amount exceeds a predetermined threshold depression amount and the vehicle speed is less than a predetermined threshold vehicle speed. The controller deactivates the shift solenoids when the throttle opening angle is equal to or less than the predetermined threshold throttle opening angle and the brake-pedal depression speed, derived on the basis of the signal representative of the brake-pedal depression amounts, exceeds a predetermined threshold depression speed.