Sequential chemotherapy with methotrexate and 5-fluorouracil (MTX/5-FU) for advanced gastric cancer was given 29 patients. The procedure consisted of weekly MTX 100 mg/m2 (i.v.) followed three hours later by 5-FU 600 mg/m2 (i.v.) with leucovorin rescue on each of the following two days. Nine of 28 patients (32.1%) showed partial response to this treatment. Response rates were 28.6% in the 21 cases with poorly differentiated adenocarcinoma and 42.9% in the 7 cases with well- or moderately-differentiated adenocarcinoma. This procedure was especially effective for primary lesions (PR 9/20: 45%) and lymphnode metastases (CR 4 + PR 4, 8/17: 47.1%). Side effects were mild leukopenia and G-I symptoms such as nausea, diarrhea and loss of appetite, except in 1 patient who died of severe myelosuppression with sepsis. We concluded that sequential MTX/5-FU therapy is fairly effective and the adjuvant chemotherapy of choice for advanced or recurrent gastric cancer with not only poorly differentiated adenocarcinoma but also well- or moderately-differentiated adenocarcinoma.