This paper deals with the new development of controlled gambling embedded in a harm-reduction context as a viable solution both for primary prevention at school and for treatment of some kinds of problematic gamblers. Pathological gambling significantly improves with psychological therapies, such as stimulus control and in vivo exposure with response prevention or cognitive interventions. In some cases psychopharmacological therapy may complement the benefits of treatment for pathological gambling when patients have comorbid depression or high impulsivity. However, in this mental disorder the goal of treatment (total abstinence or controlled gambling) is currently a controversial issue. Controlled gambling may be a therapeutic option for young gamblers or patients without severe dependence. Furthermore, controlled gambling may be a relevant issue for health education in schools, with a view to teaching teenagers how to cope with actual and virtual exposure to gambling. Likewise, the gambling industry and governments are involved in harm minimization initiatives. Thus, it is necessary to coordinate a program of research that includes the industry, science, and public representatives, based on cooperative research that will permit the introduction of controlled gambling within a global strategic framework. We discuss the relevance of this review for clinical practice and for future research, as well as the unsolved problems in this field.