Treatment with the antipsychotic clozapine is often complicated by its wide-ranging and sometimes serious adverse effect profile. A link between clozapine therapy and diabetes is well established, although the onset and severity of glucose metabolism abnormalities is variable. Recent literature also suggests there may be an association between clozapine therapy and pneumonia. We review the relevant background literature and present a case of a patient with pre-existing type 2 diabetes mellitus and chronic obstructive pulmonary disease who presented with a diabetic emergency after a relatively short period of treatment with clozapine. He went on to develop pneumonia from which he died. We discuss the implications this case, and others alike, have for early routine physical health monitoring of this patient group.