The aim was to investigate sulodexide as a possible therapeutic tool for treating micro- and macroalbuminuria in diabetic patients. Fifteen patients (13 micro- and 2 macroalbuminuric) with Type II diabetes, were treated with 600 lipoprotein-lipase releasing units of sulodexide by the intramuscular route, daily for 28 days, and followed up for 2 months. The main evaluation parameter was the albumin excretion rate. At the end of treatment, six of the 13 microalbuminuric patients showed a decrease in the albumin excretion rate, which increased again in three of the six during follow-up. In the two macroalbuminuric patients the albumin excretion rate decreased at the end of treatment and remained unchanged after a further 2 months. Overall analysis (15 patients) showed a significant decrease ( P < 0.05) in the albumin excretion rate compared with baseline. Metabolic control and blood pressure remained unchanged during the entire period of study. No adverse events were registered. It is concluded that sulodexide administration has a favourable effect in reducing the albumin excretion rate in Type II diabetic patients with micro- and macroalbuminuria.