Kidney disease is a common and costly complication [1,2] of diabetes mellitus, with individuals often requiring dialysis or renal transplantation. More than 30 % of people with insulin-dependent diabetes mellitus (IDDM) are at risk of manifest renal disease [3][4][5]. In the EURODIAB IDDM Complications Study 30.6 % of a stratified European sample of individuals with IDDM aged 15-60 years (mean diabetes duration: 15 years) had albumin excretion rates (AER) of 20 m g/min or higher. In persons with a diabetes duration of 1-5 years the rate of elevated AER was 19.3 % [6]. This high prevalence of micro-and macroalbuminuria even early in IDDM and its predictive association for both clinical nephropathy [7][8][9][10][11][12] and increased cardiovascular disease risk [6,[13][14][15] highlight the potential for early detection and effective prevention of diabetic vascular complications.The use of low protein diets has been shown to reduce the progression of nephropathy in patients with clinically overt diabetic nephropathy [16][17][18][19]. In Diabetologia (1997) Summary For people with insulin-dependent diabetes mellitus (IDDM) renal disease represents a lifethreatening and costly complication. The EURODI-AB IDDM Complications Study, a cross-sectional, clinic-based study, was designed to determine the prevalence of renal complications and putative risk factors in stratified samples of European individuals with IDDM. The present study examined the relationship between dietary protein intake and urinary albumin excretion rate (AER). Food intake was assessed centrally by a standardized 3-day dietary record. Urinary AER was determined in a central laboratory from a timed 24-h urine collection. Complete data were available from 2696 persons with IDDM from 30 centres in 16 European countries. In individuals who reported protein consumption less than 20 % of total food energy intake, mean AER was below 20 m g/min. In those in whom protein intake constituted more than 20 %, mean AER increased, a trend particularly pronounced in individuals with hypertension and/or poor metabolic control. Trends reached statistical significance for intakes of total protein (% of energy, p = 0.01) and animal protein (% of energy, p = 0.02), while no association was seen for vegetable protein (p = 0.83). These findings support the current recommendation for people with diabetes not to exceed a protein intake of 20 % of total energy. Monitoring and adjustment of dietary protein appears particularly desirable for individuals with AER exceeding 20 m g/min (approximately 30 mg/24 h), especially when arterial pressure is raised and/or diabetic control is poor. [Diabetologia (1997[Diabetologia ( ) 40: 1219[Diabetologia ( -1226