&NA;Urine polyamine content is increased in patients with colorectal malignancy and may be a useful tumor marker in the management of these patients. Urinary excretion of putrescine and spermidine was measured preoperatively and in the first week postoperatively in nine patients with inflammatory bowel disease, eight with other benign colorectal disease, and 13 with colorectal cancer. Preoperative urine putrescine levels were elevated similarly in patients with inflammatory bowel disease and malignancy. Polyamine levels were increased in all three groups in the early postoperative period. Urinary polyamine excretion did not correlate with serum CEA levels, tumor volume, or stage of disease in patients with cancer. Because elevated levels of urinary polyamines are not specific for malignancy and do not correlate with other prognostic indicators, such measurements are unlikely to be useful in tumor detection and determining prognosis. Polyamine levels, however, may prove useful in monitoring response to therapy and detecting recurrences in individual patients.