Psychomotor retardation and extrapyramidal symptoms have limited the conventional antipsychotic use. Atypical antipsychotics though widely prescribed with good tolerability and efficacy, the metabolic complications associated with them are of clinical importance. Diabetic ketoacidosis (DKA) is a fatal complication of atypical antipsychotic use. We report a case of new-onset diabetes presenting as DKA with quetiapine use.