A randomized comparative study of surgical adjuvant chemotherapy using dl-leucovorin (dl-LV) and 5-fluorouracil (5-FU) (FL-therapy) with CDDP, 5-FU, and dl-LV (PFL-therapy) was conducted. The following were the administration schedules: Arm A was 13 mg/m2 of CDDP, 300 mg/m2 of 5-FU, and 30 mg/body of dl-LV for 5 consecutive days and arm B was 300 mg/m2 of 5-FU and 30 mg/body of dl-LV for 5 consecutive days. Both regimens were followed by biweekly administration of the same dose of dl-LV and 5-FU in outpatients. Arm A was started at the 26th postoperative day and arm B at the 21st day on average. Some 26 cases composed of 11 cases of arm A and 15 cases of arm B completed the administration schedules. Only one case in arm A was complicated by local recurrence around 35 months after operation. Major toxicities were anorexia and neutropenia. Both toxicities were seen more in arm A than in arm B, showing complete recovery in all cases. These data suggest that PFL-therapy and FL-therapy seem to be possible and promising surgical adjuvant therapies for advanced colorectal carcinoma.