Two techniques for percutaneous renal biopsy were reviewed to assess their relative safety and efficacy. The safety was evaluated based on twenty-five consecutive procedures. Using a hand-held 14G spinal biopsy needle, right kidney was biopsied under real-time ultrasound control. Needle biopsy specimens were also obtained from the left kidney blindly and the procedure was compared with biopsy performed under ultrasound control. To assess the immediate effects of renal biopsy, twenty steers were slaughtered shortly after the procedure and examined. The remaining five animals were biopsied then examined daily for nine days and then slaughtered and examined. The echo-assisted technique was more reliable at retrieving an adequate specimen for histological examination (90%) than the blind biopsy technique (50%). Only one pass was made in each of the ultrasound-guided biopsies, as compared to 2-3 passes in the blindly biopsied steers. In the blindly sampled group, 2 (20%) steers developed macroscopic haematuria. No complications occurred post biopsy in the group biopsied under ultrasound guidance. Changes indicative of inflammation were not apparent in total and differential WBC counts and in albumin/ globulin ratios. The activities of aspartate aminotransferase,                   g-glutamyltransferase, creatinine kinase and lactate dehydrogenase, the percent of haematocrite and the serum concentrations of urea nitrogen, creatinine and haemoglobin remained within reference ranges. Unlike the ultrasound-guided biopsies where animals developed a steak of haematoma at the site of biopsy and six had a thin subcapsular haematoma (< 2cm), six of the ten steers used for the blind biopsy had subcapsular haematoma (< 5cm). On the cut surface, the needle used in the blind biopsy of the left kidney tended to penetrate deeper than that used in the echo-assisted biopsy of the right kidney. Changes in the peritoneum, omentum and bowel observed in slaughtered animals were negligible. It is concluded that percutaneous ultrasound-guided renal biopsy is safe, fast, cost-effective, and practical as long as it is performed properly. It is believed that this technique can be used in cattle with suspected renal disease for making an antemortem diagnosis.