Urolithiasis is a significant problem in the developed countries due to the increased number of patients with stones. Just a few decades ago open surgery was the only surgical treatment which is today, in most cases, replaced with minimally-invasive methods. One of these new methods is mini-percutaneous nephrolihotripsy. We present four patients in whom mini-percutaneous nephrolithotripsy was performed. In all patients the stone was located in the renal pelvis. In three patients the stone was in the native kidney and in one in the transplanted kidney. In all patients laser lithotripsy was successfully performed. On the control x-ray the residual fragments were not found in any patients. Mini-percutaneous nephrolithotripsy is a minimally-invasive method which is successfull in the treatment of nephfrolithiasis in native and transplanted kidneys.