OBJECTIVE - To evaluate the cumulative incidence of nephrotic-range albuminuria (NRA), the frequency of remission, and the impact on progression, we analyzed data from a prospective cohort study of type 1 diabetic patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS - All of the albuminuric type 1 diabetic patients (n = 321, 121 women), who had at least yearly measurements of glomerular filtration rate (GFR) with a 51Cr-EDTA plasma clearance technique and were followed for at least 3 years, were evaluated. NRA, defined as persistent albuminuria >2,500 mg/24 h, occurred in 126 patients (35 women) aged (mean ± SD) 34 ± 8 years, with duration of diabetes 22 ± 8 years and follow-up time from onset of NRA (median [range]) 8.7 (3.0-20.9) years. Remission of NRA was defined as sustained albuminuria <600 mg/24 h for at least 1 year. RESULTS - The cumulative incidence of NRA was 39%. Remission was induced in 28 of 126 (22%) patients; 21 were predominantly treated with ACE inhibitors, 7 with non-ACE inhibitor medications. Remission lasted 3.6 (1.0-18.1) years. More women (37%) than men (16%) obtained remission (P = 0.01). In the remission group compared with the no-remission group, mean arterial blood pressure (mean ± SEM) was reduced (102 ± 1 vs. 106 ± 1 mmHg, P < 0.01), the rate of decline in GFR was diminished (3.8 ± 0.6 vs. 7.5 ± 0.5 ml · min-1 · year-1, P < 0.001), and serum cholesterol was lower (5.3 ± 0.2 vs. 6.1 ± 0.1 mmol/1, P < 0.01) during the whole follow-up period. No difference in glycemic control was found between groups (HbA1c 9.2 vs. 9.4%, NS). CONCLUSIONS - In contrast to observations made before the use of antihypertensive treatment, our prospective observational study suggests that aggressive antihypertensive treatment with and without ACE inhibitors can induce long-lasting remission in a sizeable fraction of type 1 diabetic patients with NRA. The group of patients obtaining remission is characterized by slow progression of diabetic nephropathy and improved cardiovascular risk profile.