The development and evaluation of the Centre for Addiction and Mental Health Inventory of Gambling Situations (CAMH-IGS) is described. The CAMH-IGS is based on a cognitive-behavioural approach to addiction that sees excessive gambling as a pattern of behaviour which is learned, and which can be changed. The CAMH-IGS is designed to determine the patterns of behaviour, thoughts or feelings which may trigger problematic gambling, with the goal of developing tailored treatment and relapse-prevention approaches for clients. The information can be used in treatment planning. A sample of 524 gamblers that included 323 problem and probable pathological gamblers was used to evaluate the factor structure, reliability, and external correlations of the CAMH-IGS. The results show that the CAMH-IGS consists of 10 internally reliable subscales that can identify individual differences between clients.