Objective: A relationship has been suggested between recurrent major depression and high nicotine dependence. A similar relevance may establish a reference for further investigations evaluating the role of nicotine dependence on various psychiatric disorders. For this purpose, we assessed the frequency of smoking and nicotine dependence, according to psychiatric diagnosis in psychiatric outpatients. Methods: A total of 1036 psychiatric patients were included in this descriptive study. The participants were evaluated according to DSM IV (Diagnostic and Statistical Manual of Mental Disorders, 4th. Edition) for psychiatric disorders and Fagerström Test for Nicotine Dependence (FTND) that was applied to define smoking habits.Results: The overall smoking rate was 40.2% (n=1036), while the smoking rate of females and males was 32.6% (n=229) and 56.0% (n=187) (p<0.001) respectively. The mean age of onset of smoking, and the mean FTND score were significantly higher in men than women [The mean age of onset of smoking was 19.6 ± 6.5 years in women, and 16.8 ± 6.0 years in men (p<0.001). The mean FTND score in women and men was 3.9 ± 2.7 and 5.1 ± 2.6 (p<0.001)]. The age of onset of smoking, the number of smoking cessation trials, FTND scores, and the smoking cessation request of patients with psychotic disorders were significantly lower than patients with affective disorders and anxiety disorders (respectively p=0.008, p=0.047, p<0.001, p=0.015).Conclusion: The lower ratio of high nicotine dependence in psychotic disorder in comparison to affective and anxiety disorders may give insight to the role of nicotine in the pathogenesis of the psychiatric diseases.