Purpose Trifluridine/tipiracil (TAS-102) was effective in patients with metastatic colorectal cancer (mCRC) in a phase II Japanese trial. This regional trial evaluated the efficacy and safety of trifluridine/tipiracil in Asian patients with mCRC with or without exposure to biologic therapy. Patients and Methods This randomized, double-blind, placebo-controlled, phase III trial was conducted at 30 sites in China, the Republic of Korea, and Thailand. Patients ≥ 18 years old with histologically or cytologically confirmed adenocarcinoma of the colon or rectum and known KRAS status who were refractory or intolerant to two or more prior chemotherapy regimens were enrolled. Eligible patients were randomly assigned (2:1 ratio; minimization method) to receive trifluridine/tipiracil (twice per day orally; 5 days on and 2 days off for 2 weeks, followed by 14 days off per cycle) or placebo. The primary end point was overall survival (intent-to-treat population). Results Between October 16, 2013, and June 15, 2015, 406 patients were randomly assigned to receive trifluridine/tipiracil (n = 271) or placebo (n = 135). Risk of death was significantly lower in the trifluridine/tipiracil arm than in the placebo arm (hazard ratio for death, 0.79; 95% CI, 0.62 to 0.99; log-rank P = .035). Median overall survival was significantly longer in the trifluridine/tipiracil than in the placebo arm (7.8 months [95% CI, 7.1 to 8.8 months] v 7.1 months [95% CI, 5.9 to 8.2 months], respectively), for a median survival follow-up time of 13.8 months (95% CI, 13.1 to 15.3 months) compared with 13.4 months (95% CI, 11.6 to 17.3 months), respectively. The incidence of serious adverse events was similar between the arms (trifluridine/tipiracil, n = 63 [23.2%]; placebo, n = 32 [23.7%]). No treatment-related deaths were reported. Conclusion Trifluridine/tipiracil has a statistically significant survival benefit compared with placebo in Asian patients with mCRC refractory or intolerant to standard chemotherapies, regardless of exposure to biologic therapy. The safety profile is similar to previous reports.