Objective. The objective is to study the comorbidity rate of obsessive compulsive disorder and obsessive compulsive symptoms in patients with schizophrenia and their relation with the course of this illness. Design. 73 out-patients from Istanbul Medical Faculty Department of Psychiatry and 4th Unit of Bakirkoy Mental Hospital who met the DSM III-R criteria for schizophrenia were recruited for this study. Other inclusion criteria were being out of acute exacerbation phase of schizophrenia. Yale-Brown Obsessive-Compulsive Scale, Yale Brown Obsessive Compulsive Symptom Screening Inventory were applied to patients. Results. Comorbidity rate of obsessive-compulsive disorder in patients with schizophrenia was 9.6%, and also obsessive compulsive symptoms were detected 31% of patients. Aggressive obsessions were seen most frequently. These symptoms were also reported more frequently in the patients whose Global Assessment of Functionality score was higher than 45 points. Suicide attempts in psychiatric history were significantly higher for patients with obsessive-compulsive symptoms. Conclusion. Our findings indicate that obsessive-compulsive symptoms are seen more frequently than previously reported, and have no major effect upon the course of schizophrenia.