The automatic spring-loaded biopsy gun with 18-gauge needle was used to perform 20 renal transplant biopsies. A total of 35 needle passes were used during the 20 biopsies to obtain 31 cores of renal tissue (ratio of successful cores to passes 0.88). Nineteen of 20 biopsies (95%) resulted in renal tissue sufficient for diagnosis. One patient experienced gross hematuria that required blood transfusion and resulted in temporary ureteral clot obstruction. We believe the automatic spring-loaded biopsy gun with ultrasonic control allows rapid, accurate, and safe histologic assessment of the renal allograft, and we recommend this system for routine use.