&NA;Controversy exists regarding the role of prophylactic oophorectomy during resection for primary colorectal cancer.PURPOSE:A prospective, randomized trial was initiated to evaluate the influence of oophorectomy on recurrence and survival in patients with Dukes Stages B and C colorectal cancer.METHOD:Between November 1986 and March 1997, 155 patients were randomized to oophorectomy or no oophorectomy at laparotomy for resection of colorectal cancer.RESULTS:No incidence of gross or microscopic metastatic disease to the ovary was found among 77 patients randomized to oophorectomy, in contrast to previous reports. Preliminary crude survival curves suggested a survival benefit for oophorectomy between two and three years from surgery, but Kaplan‐Meier survival analysis indicated that this was not statistically significant and the benefit does not appear to persist at five years. Kaplan‐Meier curves of recurrence‐free survival, however, suggest a more substantial separation of the curves, with 80 percentvs.65 percent five‐year disease‐free survival for oophorectomyvs.nonoophorectomy, but further patient accrual is necessary to provide sufficient statistical power.CONCLUSIONS:Occult colorectal carcinoma metastatic to the ovaries has not been documented in this series of putative Dukes Stages B and C tumors. The possibility of a recurrence‐free survival advantage emphasizes the need to continue this preliminary work.