Internal mammary artery to pulmonary vasculature fistula is a rare condition that can be congenital or associated with coronary bypass surgery, trauma, inflammation, or neoplasia. We report six cases of symptomatic internal mammary artery to pulmonary vasculature fistula diagnosed after coronary bypass surgery using left internal mammary artery graft. (c) 2005 Elsevier Ireland Ltd. All rights reserved.