The prevalence of persistent microalbuminuria, retinopathy, and peripheral and autonomic neuropathy was assessed in 18 children and adolescents with type 1 (insulin-dependent) diabetes mellitus (IDDM) who suffered from necrobiosis lipoidica diabeticorum (NLD) and in 40 diabetics without NLD, matched for sex, age, duration of disease, and metabolic control. The mean +/- SD age of the patients was 15.1 +/- 8.6 years (range 7.9-23.9 yrs) and their duration of IDDM was 10.9 +/- 8.1 years (range 7.1-21.0 yrs). Their mean glycosylated hemoglobin level was 9.9 +/- 5.0% (7.3-16.6%) and their fructosamine level was 274 +/- 180 mumol/L (199-466 mumol/L). Patients with NLD had a higher frequency of persistent microalbuminuria (p < 0.001) and retinopathy (p < 0.001) than those without NLD. Our study suggests that children as well as adult diabetics with NLD can be at high risk for nephropathy and retinopathy; NLD can be a clue for diabetic nephropathy and retinopathy.