Aims. Researchers must develop effective strategies for disseminating research-based treatments. This study evaluates the application of a dissemination model based on principles of social marketing and diffusion theory. Design. A case study describes how the model was implemented. A qualitative design was employed to examine rates of adoption and adaptation of an early intervention program by a targeted system of addictions agencies. Setting. The interventions were developed at the Addiction Research Foundation in Toronto and disseminated to Assessment and Referral (A/R) Centres in Ontario, Canada. Participants. Study participants included the managers and a designated therapist for 33 participating A/R centres. Measurements. Managers were asked mainly open-ended questions concerning whether their agency had made a formal decision to adopt the intervention and whether therapists in their agency were using the early intervention program. "Adoption" was operationalized as offering the complete four-session intervention to at least one client. Findings. At 12 months after the completion of training workshops, 68% of 34 agencies in the target system had adopted the program while 85% of the agencies were using some components of the intervention with clients. Conclusions. The dissemination model appeared to be effective although its application proved to be time-consuming and labour-intensive. The "market analysis", systems focus and field-test components of the model appeared to contribute to its success.