Seventy-two Type I diabetic patients were divided into three groups according to 24 hour urinary albumin excretion (UalbV, mean of three urine collections): normoalbuminuric group 1 (n = 49, UalbV less than or equal to 26 mg/24 h), microalbuminuric group 2 (n = 16, 26 less than UalbV less than or equal to 250 mg/24 h), proteinuric group 3 (n = 7, UalbV greater than 250 mg/24 h). Fluorescein angiography and three cardiovascular autonomic tests were performed. Relative frequencies of ocular findings (no retinopathy/simplex retinopathy/preproliferative and proliferative retinopathy) were determined in each group: group 1 (0.31/0.63/0.06), group 2 (0.56/0.38/0.06), and group 3 (0/0.43/0.57). The most severely affected autonomic function was observed in group 3 (p less than 0.01 vs. group 1). Significant partial correlations were found between UalbV and retinopathy (p less than 0.01), UalbV, and autonomic neuropathy (p less than 0.05), retinopathy and autonomic neuropathy (p less than 0.01), and blood pressure and UalbV and/or autonomic neuropathy (p less than 0.01). No correlation was found between the variables and the previous 15 months' metabolic control. The results suggest that nephropathy, retinopathy, and autonomic neuropathy are signs of a generalized diabetic microangiopathic process whose progression may be influenced by factors other than diabetes duration and metabolic control.