BACKGROUND: To assess the prevalence of and factors associated with tobacco smoking and dependence in HIV patients. METHODS: In a one-day cross-sectional national survey of a representative sample of 82 French units specialized in HIV-infected patient care, 727 consecutive outpatients were asked to complete a self-administered questionnaire, assessing smoking habits, dependence, cessation motivation, other substance abuse, sociocultural characteristics, life with HIV and its treatment. Smoking prevalence and dependence were assessed and compared with a representative sample of the general French population. RESULTS: The questionnaire was completed by 593 (82%) patients: 12% were active or ex-intravenous drug users, 37% were homosexual men, and 43% were active smokers (compared with 31% in the French population) of whom 56% were classified as moderately or highly dependent. Fourteen percent of smokers were highly motivated and free of other substance abuse and of depressive symptoms. Smoking was independently associated with male sex (odds ratio [OR] = 2.38; 95% confidence interval [CI] 0.99-1.11), lower body mass index (OR 1.08; 95% Cl 1.14-1.03), smoking environment (OR 4.75; 95% Cl 3.02-7.49), excessive alcohol consumption (OR 2.50; 95% CI 1.20-5.23), illicit drug use (OR 2.43; 95% CI 1.41-4.19), HIV status disclosure to family (OR 1.81; 95% CI 1.16-2.85) and experience of rejection due to disclosure (OR 1.90; 95% CI 1.14-3.17). Disclosure and drug substitute usage were associated with high tobacco dependence. CONCLUSIONS: Very few HIV smokers seem to be good candidates for a standard tobacco cessation program. Tobacco reduction or cessation strategies should be adapted to this population.