BACKGROUND: About 2.3 % of the adult population in Sweden is considered to be problem gamblers, and it is estimated that only 5 % of them seek treatment. Problem gambling can have devastating effects on the economy, health and relationship, both for the problem gambler and their concerned significant other (CSO). No empirically supported program exists for the CSOs of problem gamblers. Consequently, the aim of this study is to develop and evaluate a program aimed at CSOs of treatment refusing problem gamblers. The program will be based on principles from cognitive behavioral therapy and motivational interviewing. In order to benefit as many CSOs as possible, the program will be delivered via the Internet with therapist support via email and telephone.