&NA;During the first 60 years of this century, a seemingly logical and effective operation for carcinoma of the colon was developed. The basic features of the operation are early isolation of the malignancy, wide lymphadenectomy, excision of involved adjacent organs when indicated, and adequate colonic resection. In 1977 a report appeared that purported to show that less radical procedures were equally effective in curing the disease and associated with less morbidity than the more extensive operation. This paper questions the validity of that report and gives other reported data which tend to refute that view. However, all reported series are retrospective and therefore the answer to the question posed in the title is: “We don't really know.” A plea is made for a sponsored, randomized, prospective trial to see if a lesser operation will provide the same cure rate.