Therapeutic strategies and operative techniques in urology develop rapidly. In particular, surgery becomes more and more differentiated and complex. Radiologists, especially uroradiologists wil have to provide special knowledge about urologic therapy and operative techniques in order to critically look at postoperative changes. Part I of this review will cover therapy and postoperative evaluation in nephrolitiasis, renal tumors and disease of the ureter. Using the appropriate modality at the appropriate time in postoperative course is discussed. Typical postoperative changes are shown. There is a focus on evaluation and typical radiologic findings in postoperative complications.