OBJECTIVE: To examine the association between serum Lp(a) lipoprotein concentration and clinical and angiographic outcomes five years after coronary artery bypass graft (CABG) surgery. SETTING: A regional cardiothoracic centre, Freeman Hospital, and the University Clinical Investigation Unit, Royal Victoria Infirmary, Newcastle upon Tyne. PATIENTS AND DESIGN: 353 consecutive patients (56 female, 297 male, mean age 57-2 years) undergoing first time CABG surgery for stable angina were studied prospectively. MAIN OUTCOME MEASURES: Late cardiac death (beyond 30 days) and non-fatal myocardial infarction; prevalence of angina five years after surgery in 291 (94%) survivors and vein graft patency (evaluated by patient) in 118 survivors five years after surgery. Serum Lp(a) concentration and lipid profiles were measured before operation, and 3, 6, 12, and 60 months after surgery. Lipid profiles were also measured 24 months after surgery. RESULTS: Weighted Lp(a) concentration (by tertile) was not associated with late cardiac death or with the combination of late cardiac death and non-fatal myocardial infarction, with the presence of angina, or with vein graft occlusion. The association remained non-significant if analysis was restricted to the upper tertile of LDL cholesterol (> 4.1 mmol/l) or to patients under the age of 55 years at the time of surgery. CONCLUSIONS: Serum Lp(a) concentration did not predict late cardiac death, the combination of late cardiac death and non-fatal myocardial infarction, or the prevalence of angina or vein graft occlusion five years after CABG surgery.