We investigated the influence of the severity of schizophrenia on diabetes self-care and glycemic control among outpatients with schizophrenia and diabetes. We conducted interviews with 38 participants and reviewed their clinical charts. The mean hemoglobin A1c (HbA1c) level in the full study population was 7.65%. There was no difference in the HbA1c level between two groups of subjects classified by the severity of schizophrenia. Some diabetes self-care indicators were significantly lower in patients with high Brief Psychiatric Rating Scale scores (P < .05). Although psychotic symptoms do not appear to affect glycemic control, psychotic symptoms might affect diabetes self-care behaviors in people with schizophrenia. © 2011 Elsevier Inc.