Between September 1990 and July 1991, we treated 17 patients with renal-cell carcinoma by radical nephrectomy and two patients with urothelial carcinoma of the kidney pelvis by ureteronephrectomy. Immediately after nephrectomy, perfusion of the kidneys with cold HTK solution was performed and the organs were kept in hypothermia of 8 degrees C. The tumor-free parenchyma of the kidneys was treated 4 h later with shock waves of different energy levels in an experimental shock-wave system (Siemens Company, Erlangen). Light microscopy and examinations by scanning laser microscopy were performed after treatment. High-energy shock waves (HESW) produce significant changes in the tubulary and blood-vessel system of the viable human kidney, depending on the energy applied. Although our model is limited by hypothermia of the explanted kidneys, the effects of shock waves on the organs can be studied. Our model is suitable for testing the effects of different lithotriptors on the human kidney.