The objectives were to examine the prevalence of obsessive-compulsive disorder (OCD) in hospitalized patients with schizophrenia and to compare the clinical, cognitive, and functional characteristics of schizophrenia patients with and without OCD. This cross-sectional study, performed between May and August 2018, enrolled 308 patients (200 men and 108 women). The prevalence of OCD in patients with schizophrenia was 3.2%. An increase in patients having a mild β was significantly associated with higher social relationship score (β = 1.68) and the Memory Functioning Scale-Informant (MFS-I) version (β = 5.67). OCD did not affect the positive and negative symptoms of these patients. The prevalence of OCD in these patients was low (3.2%). Schizophrenia patients with and without OCD have comparable clinical profiles with few exceptions. The existence of OCD may affect the social relationship quality of life and the MFS-I version.