This study was designed to evaluate the antitumor efficacy and feasibility of postoperative adjuvant metronomic chemotherapy using weekly low-dosage CPT-11 and UFT in colorectal cancer at high risk to recurrence. A total of 49 patients (24 stage IIIb and 25 distant metastasis) who underwent a R0 operation were enrolled in this prospective study. Forty mg/m2 of CPT-11 were administered on day 1, day 8, and on day 15 in 28-day cycles. A dosage of 335 mg/m2/day of UFT was given perorally on daily schedule. Cycles were repeated for 6 months, and were followed by UFT alone for further 6 months. One or more adverse effects were seen in 43 of the 49 patients. However, most of these effects were mild at grade 1 or 2: with only nausea in 3 patients, vomiting in 2, leucopenia in 2 and neutropenia in 2 at grade 3. The overall survival rates were favorable both in the stage IIIb group (5-year: 73%) and in the distant metastases group (5-year: 62%). Postoperative adjuvant metronomic chemotherapy using weekly low-dosage CPT-11 and UFT might be safe and feasible and prolong survival time in colorectal cancer at high risk to recurrence.