OBJECTIVE To examine the impact of diabetic state on the concentrations of lipoprotein(a) [Lp(a)] in patients with non-insulin-dependent diabetes mellitus (NIDDM) and the correlation between angiographic coronary artery disease (CAD) and serum Lp(a) concentrations in NIDDM. METHODS In this cross-sectional study of 26 patients with NIDDM and 19 nondiabetic sex- and age-matched patients who underwent coronary angiography. CAD was assessed visually using coronary artery score (CAS), and plasma Lp(a) was measured by an enzyme-linked immunosorbent assay. METHODS The study was performed in an internal medicine clinic at a university hospital. METHODS Twenty-six age- and sex-matched patients with NIDDM and 19 control patients without diabetes. RESULTS There was no significant difference between the Lp(a) concentrations of patients with NIDDM and nondiabetic subjects (P > 0.05). When patients with NIDDM were stratified by absence or presence of CAD, patients with CAD had higher levels of Lp(a) (P < 0.05). However, there was no significant correlation between the concentrations of Lp(a) and CAS (P > 0.05). CONCLUSIONS Diabetic state does not have any impact on Lp(a) concentrations. Lp(a) excess seems to be atherogenic in patients with NIDDM as shown in nondiabetic patients in previous studies. Although diabetic patients with CAD have higher Lp(a) concentrations than the diabetic patients without CAD, Lp(a) levels were not correlated with CAS.