There is provided a combustion control system for a direct-injection spark-ignition internal combustion engine, including a fuel injection valve that injects fuel directly into a cylinder of the engine to form an air-fuel mixture in a combustion chamber of the engine cylinder, a spark plug that ignites the air-fuel mixture, and a control unit that performs combustion retard control to set an ignition timing of the spark plug at a point after compression top dead center and set an injection period of the fuel injection valve at a time after compression top dead center and before the ignition timing in such a manner that a time interval from a start point of the injection period to the ignition timing increases with decrease in a temperature in the engine cylinder at a cold start of the engine.