Piperacillin/tazobactam (PT) is a commonly prescribed antibiotic and is generally considered safe. During treatment with piperacillin/tazobactam bone marrow suppression can rarely be seen as a serious adverse effect. We report here a case of PT induced bone marrow suppression. A 58 year old man was being treated with PT for empyema. After 20 days of treatment, he developed neutropenia and thrombocytopenia.