Abstract Background: Antiphospholipid (APL) antibodies are a heterogenous group of antibodies that have been associated with an increase in bleeding complications and a marked increase in thrombotic events, both of which result in significant patient morbidity and mortality. Patients and methods: A retrospective analysis of patients identified to be positive for APL via a university thrombosis registry who had cardiovascular surgery between 1989 and 1994. Results: Seventy-one patients positive for APL antibodies were identified. Of those patients, 19 had cardiovascular surgical procedures (11 women and 8 men, mean age 58.4 years, range 38 to 78). A total of 48 cardiovascular surgical procedures (mean 2.5 procedures/patient) were performed in the 19 patients. These procedures included 13 lower-extremity reconstructions, 11 upper-extremity reconstructions/fistulas, 8 cardiac valve replacements, 5 coronary artery by-pass procedures, 5 major amputations, 4 infrarenal aortic reconstructions, and 2 carotid endarterectomies. Sixteen of the 19 patients (84.2%) suffered major postoperative complications. These included 16 thrombosed gratts, 5 strokes, 5 major bleeding events, 2 pulmonary emboli, and 2 myocardial infarctions. Ultimately, 12 of the 19 patients (63.2%) died of complications related to surgery. Conclusions: This series of patients confirms that patients with circulating APL antibodies are prone to excessive postoperative morbidity and mortality after cardiovascular surgical procedures. The presence of APL antibodies may be a marker of increased risk of complications after cardiovascular surgery.