Prevalence of diabetic nephropathy varies in different racial groups, being especially high in communities that have abandoned an active traditional living and embraced a modern but sedentary life-style. As a new and rapidly developing country, Saudi Arabia has witnessed impressive changes in socio-economic growth and development and concurrently, a disturbing trend in non-insulin-dependent diabetes mellitus (NIDDM). These observations therefore prompted us to investigate the prevalence of microalbuminuria among Saudi Arabians with NIDDM. Two hundred and eleven patients attending a large Diabetic Clinic in Riyadh were screened for microalbuminuria (30-300 mg/24 h). Twenty-seven subjects had clinical proteinuria (dipstick-positive) and were excluded, leaving 184 cases for analysis. Seventy-six subjects (76/184, 41.3%) had microalbuminuria. These subjects had higher fasting plasma glucose concentrations (P = 0.002) and greater body mass index (P = 0.049) than subjects with normal albumin excretion rate (< 30 mg/24 h). There were no significant differences between subjects with and without microalbuminuria with regards to fasting total plasma cholesterol and triglycerides concentrations, frequency of hypertension, duration of diabetes or type of therapy for diabetes. In multivariate analysis, glycaemia (P < 0.005) and years since diagnosis of diabetes (P = 0.05) remained independently associated with albumin excretion rate. We conclude that microalbuminuria is exceedingly common in a clinic-based population of Saudi Arabians with NIDDM and its presence is closely related to glycaemic control. Whether the prevalence of microalbuminuria is truly increased in the diabetic population at large in Saudi Arabia must now await further population-based studies.