This report describes recurrent respiratory distress following vincristine administration to a cat with chronic lymphocytic leukaemia. The cat was treated with a combination of vincristine, chlorambucil and prednisolone with initial success. After approximately 4 months, dyspnoea developed within 6 h of vincristine administration. Emergency therapy was instituted resulting in a full recovery. Further vincristine was administered; dyspnoea was similarly noted after all but one of these treatments. Dyspnoeic episodes were not attributable to alterations in vincristine dose or method of administration. The repeated temporal association was consistent with a suspected adverse drug reaction to vincristine.