Flow cytometry DNA measurements were carried out on colorectal carcinomas from a series of 33 patients who have since been followed for three to four years. The tumors could be subclassified by this technique into 15 that had near-diploid DNA and 18 that were aneuploid. Prior reports had suggested that the near-diploid tumors carry a better prognosis than aneuploid tumors, but in this study the distribution by Dukes' stage and survival were the same in both groups.