D Arcy reports on an empirical investigation of the impact of four security countermeasures (security policies, security awareness program, computer monitoring, preventive security software) on IS misuse. Using the framework of general deterrence theory, he develops and tests a conceptual model using survey responses from 507 professionals. He finds support for the effectiveness of security policies, security awareness programs, and computer monitoring in deterring IS misuse. Preventive security software appears only moderately effective. The results also suggest that the deterrent effectiveness of security countermeasures vary based on computer self-efficacy and the amount of time spent telecommuting. D Arcy s findings help explain the relationships between security countermeasures and IS misuse, while reaffirming the applicability of general deterrence theory to the IS security domain.