Neoplasms of the upper abdomen involve complex problems for radiotherapy. In fact, the anatomical structures are close to each other, lymphatic vessels are numerous and complex, there are organs of low radiation tolerance whose reciprocal position is of difficult assessment and finally there is high visceral mobility due to the diaphragmatic movements. Moreover most organs cannot be identified with the simulator and bone references are of little use. Therefore, treatment of these sites requires the routine application of quality assurance programs, checks of treatment reproducibility, in particular: In a number of clinical settings, CT study of the region (in treatment position) must be included in treatment planning and set-up with simulator and fluoroscopy. Before, during, and after radiotherapy, clinical exams and laboratory tests should be performed to assess the integrity of critical organs.