The prognostic significance of microalbuminuria, macroalbuminuria and other putative risk factors for mortality in insulin-dependent diabetic patients were evaluated in a 10 year prospective study. We identified 939 insulin-dependent diabetic patients; 593 patients had normoalbuminuria (< or = 30 mg/24 h), 181 had microalbuminuria (31-299 mg/24 h), and 165 had macroalbuminuria (> or = 300 mg/24 h). Fifteen percent of patients with normoalbuminuria, 25% with microalbuminuria and 44% with macroalbuminuria at baseline died during follow-up (p < or = 0.01). Significant predictors of all-cause mortality were male sex, age, height, smoking, low social class, urinary albumin excretion, hypertension, serum creatinine, and HbA1c. Age, smoking, microalbuminuria, overt nephropathy, and hypertension were significant predictors of cardiovascular mortality. The mortality in patients with microalbuminuria was only slightly increased compared to patients with normoalbuminuria. Median survival after onset of overt diabetic nephropathy was 13.9 (11.8 to 17.2) years. Abnormally elevated urinary albumin excretion and other potentially modifiable risk factors such as hypertension, smoking, poor glycaemic control and social class predicts increased mortality in insulin-dependent diabetic patients.