Background: A minority of individuals with problematic alcohol use effectively seek help. Moreover, dropouts from care are not uncommon. It remains a major concern for health professionals, as adherence to treatment is significantly associated with better physical and psychological outcomes. Objectives: The main aim of this research was to assess what factors could distinguish patients with problematic alcohol use who dropped out from those who did not. Methods: The sample included 150 patients followed-up in an outpatient treatment center in France for a problematic alcohol use. Two measurement times were planned: at the first appointment and after six month of treatment. A large set of individual, environmental and institutional variables were considered to compare both subgroups. Results: Patients who dropped out mostly differ from patients who did not with a higher level of alcohol-related problems, ambivalence, inclinations to use the substance, number of missed appointments. Significant results were also observed regarding a lower time gap between the first contact with the center and the first appointment, as well as the season of the last appointment. Conclusions: Tailored motivational interventions could be offered to ambivalent patients, especially during the beginning of the treatment and some significant periods of the year. A particular focus should be brought on patients presenting such profiles in terms of level of alcohol problems, inclinations to drink and motivation to change. Overall, the study provides elements to better understand what may bring one patient to drop out of the treatment, and to improve the continuity of care.