Sufficient tissue yield is essential for renal biopsy. We have developed a simple automated renal biopsy device (Chen device) that constantly obtains more tissue. Since the Bard device is extensively used around the world, we compared our device with the Bard device. Pediatric patients were biopsied with either the Chen (n=247) or Bard (n=200) devices. No major complications were encountered and the incidence of minor complications was comparable between two devices. However, the average length of tissue obtained by the Chen device per biopsy (1.78±0.73 cm) was significantly longer than that obtained by the Bard device (1.23±0.45 cm). Accordingly, 61.94% of biopsies with the Chen device had 20 or more glomeruli, whereas only 18% of biopsies with the Bard device had this number (p<0.001). Thus, the Chen device has the advantage of obtaining more renal tissue per biopsy while being equally efficient and safe as the Bard device.