Reports of chylothorax (CT) following median sternotomy are rare, amounting so far to 16 cases in the English literature, of which 6 were cases of postcoronary artery bypass grafting (CABG). This report deals with an additional case of a 70-year-old woman who developed left pleural chylous effusion following CABG. It is suggested that the incidence of this type of pleural effusion is considerably greater than the few cases hitherto reported. Moreover, as CT may produce serious pulmonary and/or pleural functional impairment, it is proposed that a diagnostic tap be performed more often in cases of post CABG pleural effusion and that preventive drainage be instituted when CT is diagnosed.