At the moment of surgical intervention, colorectal cancer involves adjacent tissues or organs in a percentage of cases ranging between 5% and 12%. "En bloc" resection of these tumors, when not associated with distant metastasis, allows survival at 5 years in from 32% to 79% of cases. The authors discuss their personal experience on the subject of extended resection for carcinoma of the large intestine, in order to evaluate not only the possible anatomico-clinical peculiarities but also both short and long term results. In the period from 1976 to 1993 1164 patients underwent surgery for colorectal cancer, in 791 cases (68%) with a curative aim. 71 patients underwent extended resection, in 59 cases for the curative treatment of a primary tumor and in 12 for the treatment of a local recurrence (LR). Pathologic examination revealed neoplastic infiltration into at least one of the organs removed with the tumor in 43 cases (61%). It must, however, be pointed out that the above frequency was considerably higher (92%) when extended resection was carried out for LR than in cases of exeresis of primary cancers (54%). The reported results show that extended resection leads to potentially higher morbidity and mortality than can be observed after standard resection, but that, at the same time, it proves to be the only treatment able to provide these patients with good prospects for fairly long-term survival. Recourse to this procedure must therefore always be out of necessity, furthermore the extension of demolition must be adapted to the operative finding.(ABSTRACT TRUNCATED AT 250 WORDS)