Objective To determine the influence of schizophrenia patients with diabetes on cognitive function.Methods Altogether 78 schizophrenia patients with diabetes and 118 patients with schizophrenia were enrolled and Negative and Positive Syndrome Scale,Wechsler Memory Scale-Revised Visual Reproduction Test,Wechsler Adult Intelligence Scale-Revised Digit Symbol Test,Computerized Wisconsin Card Sorting Test,Trail Making Tests,Part A and B,and Wechsler Adult Intelligence Scale-Revised Digit Span Test were used to assess the clinical syndrome and to test the cognitive function.ResultsImpairment of Processing Speed,Attention/Working Memory,Executive Functioning and Visual Memory in schizophrenia patients with diabetes was significantly poorer than that of the schizophrenia patients ( all P ＜ 0.05 ).WAIS-R Digit Symbol Test score and Trail Making Test A and B scores were associated with diabetes duration and age at diabetes onset (P ＜0.01 ).Conclusion The impairment of cognitive function in schizophrenia patients with diabetes is severer than schizophrenia patients,suggesting that the prevention and management of diabetes may improve cognitive outcome in schizophrenia patients.