This study described the prevalence and correlates of comorbid moderate–severe depressive symptoms (comorbid depression thereafter) and their association with quality of life (QOL) in schizophrenia patients treated in primary care. 623 schizophrenia patients were enrolled. Patients’ socio-demographic and clinical characteristics including comorbid depression [defined as a total score of 18 or above on the Montgomery–Asberg Depression Rating Scale (MADRS)] were recorded. Depressive symptoms (defined as a total score of 9 or above on the MADRS) were present in 54.1 % of patients, while 17.7 % had comorbid depression. Analysis of covariance revealed that comorbid depression was significantly associated with lower mental QOL. Multiple logistic regression analysis revealed that more severe positive and negative symptoms, anxiety symptoms, use of first-generation antipsychotics and antidepressants, were independently associated with comorbid depression. Given the negative association between comorbid depression and QOL, attempts to address comorbid depression in schizophrenia patients treated in primary care should be made.