All diabetic children (n = 113) under 19 years old and with more than 2 years of diabetes attending the Steno Memorial Hospital in 1987 were studied. Normal urinary albumin excretion (less than 30 mg 24 h-1) was found in 96 patients (85%), 15 had microalbuminuria (30-300 mg 24 h-1) (13%), and 2 patients were proteinuric (greater than 300 mg 24 h-1) (2%). Retinal morphology was evaluated by colour fundus photography. Background retinopathy was more frequent in the group with elevated albumin excretion (71%) than in a matched normoalbuminuric group (20%, 2p less than 0.001). Long-term blood glucose control was assessed from all previous HbA1c measurements in the hospital records, an average of nine per patient. The mean observation period was 48 (3-76) months. Children with elevated albumin excretion had a higher mean HbA1c than children with normal urinary albumin excretion (10.3 +/- 1.9 vs 9.2 +/- 1.3% (+/- SD), 2p less than 0.05). Children with retinopathy had an HbA1c of 9.9 +/- 1.7 vs 9.0 +/- 1.2% in patients without retinopathy (2p less than 0.01).