The increase of urinary albumin excretion has a predictive value for cardiovascular disease in insulin-dependent and non insulin-dependent diabetics. To study the relationship between urinary albumin excretion and serum lipids, 380 non insulin-dependent diabetics, 40 to 75 yr old, with urinary albumin excretion from 0 to 200 mg/l, and normal serum creatinine (less than 150 mumol/l), were surveyed. Urinary albumin excretion, was related positively to age (r2 = 0.014; p = 0.02), to systolic blood pressure (r2 = 0.073, p = 0.0001) and diastolic blood pressure (r2 = 0.052, p = 0.0001); a negative correlation existed with HDL-cholesterol (r2 = 0.043, p = 0.0001) and Apoprotein A1 (r2 = 0.044, p = 0.0001). A stepwise regression analysis was performed and resulted in three independently contributing variables related to urinary albumin excretion: First systolic blood pressure (F = 36), second Apoprotein A1 (F 24), third hemoglobin A1C (F = 6). The presence of hypertension or insulin therapy did not modify these findings. In conclusion, serum lipid seems an important determinant of urinary albumin excretion in non insulin-dependent diabetics.