One hundred and twenty percutaneous renal biopsies performed in 104 patients aged 1 month to 15 years were analysed. Ultrasound examination was used for localization of the kidneys. Adequate renal tissue was obtained in 103 biopsies, with an overall success rate of 85.8%. The most frequent complication was gross haematuria, which occurred in 32 biopsies, but only 5 children required blood transfusion. Nineteen patients developed perirenal haematoma; 2 of these were symptomatic. Arteriovenous fistula was diagnosed in 2 patients. One patient died secondary to intestinal perforation. Serious complications were noted in patients with chronic renal failure. The success and complication rates in 10 patients less than 1 year of age were comparable with the rest of the group. The frequency of serious complications on renal biopsy in the present study was slightly higher than in the more developed countries.