This case report comprises three cases of antipsychotic drug-induced hypoglycemia and hypothermia. The mechanisms behind these side-effects are not known, but in hypoglycemia we describe signs of inappropriate insulin secretion. We assume that antipsychotic drug-induced hypoglycemia and hypothermia are underdiagnosed. Antipsychotic drugs are, however, widely used and these rare adverse-effects may occur in the clinical practice. It is of utmost importance to measure blood glucose and body temperature of patients taking these drugs who have unspecific symptoms.