Objective: We report a schizophrenic woman who developed new-onset diabetes mellitus (DM) and hyperlipidemia after having taken clozapine for three years. Case Report: A 39-year-old Hakka woman with chronic schizophrenia who had multiple hospitalizations for acute psychiatric symptoms, had been treated with flupenthixol, sulpiride, clopenthixol, risperidone, flupenthixol depot injection, and 20 treatments with bilateral electroconvulsive therapy (ECT). These treatments had not caused DM or hyperlipidemia. However, her treatment was later modified and clozapine (300 mg/d) was started. Although the addition of clozapine improved her psychotic symptoms, she developed new-onset DM and hyperlipidemia three years later. At last follow up in April of 2005, she required antidiabetic and antilipid medications for controlling DM and hyperlipidemia. Conclusion: The findings of this case stress the importance of early recognition of developing hyperglycemia and hyperlipidemia when schizophrenic patients are treated with clozapine.