Microalbuminuria (or urinary albumin excretion rates (AER) above normal limits) is associated with coronary heart disease (CHD) particularly in diabetics. To determine the sensitivity and specificity of AER for CHD in a non-diabetic population we prospectively studied 115 consecutive patients undergoing coronary angiography and 66 undergoing exercise electrocardiography (ECG). There was no relationship between AER and the severity of CHD determined by angiography (Gensini-scored). While microalbuminuria (AER > 20 micrograms/minute) was 91% specific it had low sensitivity (12%). Microalbuminuria is not a sensitive indicator of CHD in a non-diabetic population.