This randomised, open-label trial compared oral tegafur (FT)/leucovorin (LV) with the intravenous bolus 5-fluorouracil (5-FU)/LV as first-line chemotherapy for advanced colorectal cancer (CRC). Patients were randomised to receive oral FT 750 mg/m2/day for 21 days and LV 15 mg/m2 every 8 h in cycles repeated every 28 days (n=114), or intravenous LV 20 mg/m2 followed by 5-FU 425 mg/m2 daily for 5 days every 4 weeks for 2 cycles, and later every 5 weeks (n=123). Response rate was significantly higher in the FT/LV arm (27%, 95% CI 19-35) than in the 5-FU/LV arm (13%, 95% CI 7-19) (p<0.004). The median time to progression was 5.9 months (95% CI, 5.3-6.5; FT/LV arm) and 6.2 months (95% CI, 5.4-6.9; 5-FU/LV arm). Median overall survival was 12.4 months (95% CI, 10.3-14.5 months; FT/LV arm) and 12.2 months (95% CI, 8.9-15.7 months; 5-FU/LV arm) (p=n.s.; hazard ratio FT/LV:5-FU/LV=1.02). 5-FU/LV showed a higher incidence of grade 3/4 neutropenia (4.1 vs. 0%). Non-hematological toxicities showed similar incidences in the two treatment arms. Oral FT/LV was more active than IV 5-FU/LV in terms of objective response rate with similar overall survival, and with a favorable toxicity profile. This makes FT/LV a valid alternative to the IV 5-FU schedule in CRC patients.