We evaluated whether the location of a smoking cessation clinic in a hospital enhances the success rate compared to that found in the literature, regardless of the type of treatment. We assessed the results and identified prognostic factors of success in 12 smoking cessation clinics situated in 12 hospitals of the Assistance publique-Hôpitaux de Paris (AP-HP). The clinics were included in the study after a call for participation. The response rate was 60%. The study design was prospective, multicentric and descriptive. The study lasted 9 months. Follow-up took place 3 and 6 months after the first visit. The definition of success was self-reported total abstinence from cigarette smoking during the month preceding the 6-month follow-up. Success rate was 27%, failures were 66%, and 7% were lost to follow-up. Prognostic factors of success were not related to the hospital setting. We conclude that for a number of structural reasons that we explain, according to this study, the location of smoking cessation clinics in hospitals does not enhance their success rate compared to that found in the literature.