A nondiabetic young male patient in hypomanic phase of bipolar disorder on maintenance treatment with sodium valproate, developed transient episode of acute pancreatitis and diabetic ketoacidosis after addition of chlorpromazine and halopridol. It subsided completely within six weeks and his blood sugar was normal without any antidiabetic therapy. Simultaneous occurrence of acute pancreatitis and diabetic ketoacidosis is reported as a very rare complication of combination of antipsychotic drugs sodium valproate, chlorpromazine and haloperidol. Blood sugar should be periodically monitored in patients on sodium valproate and antipsychotic medication.