A control system for a marine propulsion device capable of driving a propeller (18) by either an engine (23) or a motor (25) is provided. The control system includes a first memory (40a) configured to hold first information for identifying whether the control system has shut down normally or abnormally even during a reset period of the control system, a second memory (22a, 26a) configured to hold second information indicating control states of the engine and the motor even during the reset period of the control system, and a controller (40). The controlled is configured or programmed to start controlling the engine and the motor, based on the second information held in the second memory, in a case where the first information held in the first memory indicates an abnormal shutdown of the control system at a startup of the control system.