In the present study we investigated serum lipoprotein(a) [Lp(a)] levels, plasma lipids, the serum phospholipid polyunsaturated fatty acid profile and correlates of serum Lp(a) in healthy free-living female vegetarians ( n = 50) and omnivores ( n = 24) to assess differences which may have implications for cardiovascular risk. Dietary saturated fat and total plasma cholesterol were significantly lower in the vegetarians compared with omnivores. The mean serum Lp(a) concentration was lower in the vegetarians (171 mg/l) than in the omnivores (247 mg/l). The serum Lp(a) concentration was significantly negatively correlated with carbohydrate intake (as % of energy), and positively correlated with plasma total cholesterol. Compared with the omnivores, the vegetarians had significantly lower concentrations of 20:3, n -6, 20:4, n -6, 22:5, n -6, 20:5, n -3, 22:6, n -3 and total n -6 and n -3 polyunsaturated fatty acids, and a lower n -3/ n -6 polyunsaturated fatty acid ratio, in serum phospholipids. Lower concentrations of plasma total cholesterol, serum phospholipid total fatty acids, total saturated fatty acids and arachidonic acid, and a tendency towards a lower serum Lp(a) concentration, in vegetarians may have beneficial effects on cardiovascular disease risk. However, the decreased concentration of serum phospholipid n -3 polyunsaturated fatty acids may potentially promote thrombotic risk. Based on the present data, it would seem appropriate for omnivores to reduce their dietary intake of total fat and saturated fat in order to decrease their plasma cholesterol, and vegetarians should perhaps increase their dietary intake of n -3 polyunsaturated fatty acids, and thus improve the balance of n -3/ n -6, in order to reduce any thrombotic tendency that might increase their generally low risk of cardiovascular disease.