In the course of 5 years, 582 ultrasound guided percutaneous renal biopsies were performed in 558 patients. Kidney tissue was obtained in 507 patients (90.9%), and in 485 (86.9%) the obtained sample was sufficient to establish the diagnosis. Complications following renal biopsies were observed in 221 patients, or 38% of total biopsies. There were 212 (36.4%) clinically moderate complications. The most frequent ones were asymptomatic hematomae (32.6%), and infrequently lumbar pain (2.4%) and hematuriae lasting less than 12 hours (1.4%). In 9 patients 10 (1.7%) serious clinical complications in the form of hematuria lasting more than 12 h (1%), large perirenal hematomae (0.5%) and urinary infections (0.2%). In the older age group and in patients with pronounced renal failure no significant difference in the incidence of complications was observed. Ultrasound guided percutaneous renal biopsy is a safe diagnostic method, and the associated complications do not seriously curb its use. The therapy of complications is primarily conservative, and only rarely surgical.