Introduction: Major depressive disorder (MDD) is the most frequent comorbid psychiatric condition associated with obsessive-compulsive disorder (OCD). This study aimed to evaluate the prevalence of current depression in OCD, differences in socio-demographic and clinical characteristics, and obsessive-compulsive symptoms between OCD patients with and without depression. Additionally, factors associated with comorbid depression were investigated in our study.Methods: In total, 140 OCD patients, of which 63 were OCD patients with MDD (OCD+MDD, n=63) and 77 were OCD patients without depression (OCD-MDD, n=77) were included in the study. All patients were diagnosed with OCD using the Structured Clinical Interview for DSM-IV. The Yale-Brown Obsessive-Compulsive Scale, Beck Anxiety Scale, and Beck Depression Scale were administered to all patients. After the socio-demographic and clinical variables and scales were accomplished, the OCD patients divided into two groups as OCD with or without depression and we compared their mean scores of the variables and scales. Univariate analyses were followed by logistic regression Results: There were no significant differences in age, gender, marital status, period without treatment, profession, medical and family history, andsocialsupportbetweenthetwogroups.Anxiety,depression,and obsession and compulsion scores were significantly higher in the OCD+MDD group. The avoidance, insight, instability, and retardation scores of the OCD+MDD group were also significantly higher than those of the OCD-MDD group.Conclusion: Our study suggests that many factors are strongly associated with depression in OCD. Positive correlations between poor insight, severity of obsession and compulsion, and stressful life events during the last six months increased the risk of depression in OCD. Our study suggests that high level of avoidance, instability and retardation, history of suicidal attempt, and delayed treatment are other notable factors associated with the development of depression in OCD