The S-1 +biweekly docetaxel (DOC) combination therapy was evaluated for advanced or recurrent gastric cancer patients. This combination therapy was evaluated in vitro using the nude rat-gastric cancer xenograft system. S-1 alone or DOC alone showed antitumor activity, and the antitumor activity was synergistic when two drugs were combined. In clinical settings, the schedule was S-1 80 mg/m2 (day 1-14, orally) and DOC (day 1 and day 15, intravenously) followed by a 2-week rest. In phase I study, the dose of DOC was evaluated, and a recommended dose for phase II was determined as 35 mg/m2. The entry for phase II study was completed, and the preliminary results of 33 patients showed the response rate of 21.2%. The incidence of more than grade 3 adverse effects was 29%(neutropenia, leukocytopenia, anorexia and mucositis). The S-1 +biweekly DOC combination therapy can be a candidate for outpatient chemotherapy for advanced or recurrent gastric cancer.