Objective: The relationship between obsessive compulsive disorder and schizophrenia has been a matter of dispute for ages. This study aimed to investigate the differences between schizophrenia with obsessive compulsive symptoms (OCS) and schizophrenia without OCS in affecting positive and negative symptoms of schizophrenia. 
Methods: Study participants comprised 30 patients with schizophrenia with OCS and 30 patients with schizophrenia without OCS which were enrolled through convenience sampling method from Roozbeh Hospital, Tehran, Iran. Diagnosis was made by a psychiatrist using SCID-I and the data were gathered using positive and negative syndrome scale (PANSS) and Yale-Brown obsessive-compulsive scale (Y-BOC). MANCOVA test was used for analyzing data. 
Results: Results indicated that there was not any difference between schizophrenia with OCS group and schizophrenia without OCS group with regard to positive symptoms, but the difference in negative symptoms between two groups was significant. 
Conclusion: The present study reveals that OCS may be a protective factor for schizophrenia. Further studies are needed to investigate other factors and mediators involved in this association