Objective: This study aimed to compare the burden of caregivers of patients with bipolar disorder and schizo-phrenia, and its relationship with sociodemographic variables of the subjects and clinical features of the disorders. Methods: Sixty-two schizophrenia and 62 bipolar affective disorder-I patients with their caregivers who consulted Uludag University Medical Faculty outpatient clinic of Department of Psychiatry were enrolled to the study. Patients with schizophrenia were assessed on Positive and Negative Syndrome Scale, patients with bipolar affective disorder-I were assessed on Hamilton Depression Rating Scale (HDRS) and Young Mania Rat¬ing Scale. Global Assessment of Functioning (GAF) Scale, sociodemographic and Clinical Characteristics Data Form were applied to each patient. Caregivers of the patients were assessed on HDRS, Hamilton Anxiety Rating Scale (HARS), Zarit Caregiver Burden Scale (ZCBS) and Socio-demographic Characteristics Data Form. Results: It is found that the scores of ZCBS for schizophrenia patients caregivers were significantly higher than those bipolar affective disorder patients caregivers. Scores of HDRS and HARS were significantly correlated with the score of ZCBS in both care-giver groups. Conclusion: Caregivers of schizophrenia patients are more likely to be affected negatively than those of bipolar affective disorder patients, therefore psychological support should be considered for caregivers. [Anadolu Psikiyatri Derg 2018; 19(5.000): 451-458]