One hundred forty percutaneous renal biopsies were done on the transplanted kidneys of 45 patients under television-monitored fluoroscopy. Insufficient tissue was obtained on six occasions; rebiopsy was successful in all instances. Thirteen patients developed macroscopic hematuria postbiopsy, but none required transfusion or nephrectomy. This procedure is safe and associated with a high yield. Open renal biopsy was performed on 20 patients. Macroscopic hematuria occurred in five patients, wound hematoma in two, and wound infection in three; thus, the incidence of complications was much higher following open biopsy.