An elevated blood level of lipoprotein (a) [Lp(a)] has been studied as an independent risk factor for coronary artery disease. We report a series of nine consecutive patients with clinical onset or recurrence of coronary artery disease who presented without treatable atherosclerosis risk factors, five of whom had elevated Lp (a) blood levels. Indications for measuring Lp (a) levels and usefulness of niacin therapy are reviewed.