Abstract: A robbery deterrent apparatus and method is provided for convenience stores or other businesses vulnerable to armed robbery, in which a would-be armed robber is incapacitated by an aerosol agent that is delivered in a predetermined pattern within the store. In a preferred embodiment, the aerosol incapacitating agent is delivered immediately upon the detection of a firearm discharge, or after a short delay in response to an employee activated trigger. The aerosol incapacitating agent may be accompanied by a marking agent, such as ultraviolet dye, to assist authorities in capturing and identifying the would-be armed robber in the event he or she is able to escape the store after the robbery attempt.