A chain driven gate and security system is provided. The system includes a gate which is opened and closed by a gate operator. The gate operator includes a chain and a motor having a rotatable sprocket for engaging the links of a chain. The gate and security system includes a sensor for detecting whether the chain has been severed, an alarm for producing a visible or audible alert, and a processor connected to the motor, sensor and alarm. The processor activates an alarm in the event that the processor indicates that the gates should be closed, but that the chain has been severed.