Twenty-four hour urinary albumin concentrations were measured in 113 (mean age 51.1 years) non-insulin-dependent (NIDDM) Nigerian diabetics (50 males, 63 females). A high prevalence of microalbuminuria (> or = 30 mg/24 hour) was observed in male (54%) as well as female diabetics (59%). Microalbuminuria was also observed in a high proportion of diabetics (52%) with a short duration (< 5 years) of disease. Elevated blood pressure and retinopathy were present in 41% and 16% of patients respectively. Among the 49 patients with normoalbuminuria (< 30 mg/24 hour), six (12%) had retinopathy compared with 12 (18%) in the microalbuminuria group. Diastolic blood pressure levels were significantly higher (P < 0.01) in male diabetics with retinopathy but this was not associated with higher albuminuria. Urinary albumin concentrations were not influenced by elevated blood pressure. There were no significant differences in age, duration of diabetes, blood pressure or serum creatinine between diabetics with and without microalbuminuria. These results suggest that though there is a high prevalence of microalbuminuria amongst NIDDM Nigerian diabetics it may not predict retinopathy and occurs independently of either glycaemic control or elevated blood pressure levels.