Clozapine is used in the treatment of resistant schizophrenia. It is used as a reserve drug mainly because of its adverse effect profile affecting gastrointestinal, haematological and cardiorespiratory systems. Cardiac side effects are uncommon but could be potentially life threatening, hence early recognition and active monitoring are essential to prevent serious cardiac side effects. A case of pericarditis with pericardial effusion is described in a patient who was recently started on clozapine which disappeared within 1 week after discontinuation of clozapine.