A Phase II study was performed to evaluate the activity and toxicity of 5-fluorouracil, leucovorin, Adriamycin, and cisplatin combination chemotherapy (FLAP) in patients with previously untreated advanced gastric and gastroesophageal (GE) junction adenocarcinoma. Forty-two consecutive patients were enrolled to received FLAP in this multi-institutional trial. Response, toxicity, and survival data were noted. Fifteen of 42 (36%) patients demonstrated objective responses, with two complete responses (5%) and 13 partial responses (31%). The median time to disease progression was 17 weeks, and the overall survival duration was 30 weeks. Myelosuppression was significant, requiring dose modifications, but there were no treatment-related deaths. FLAP is an active regimen in the treatment of advanced gastric and GE junction adenocarcinoma. We are presently using this regimen in the neoadjuvant setting in patients with gastric and GE junction cancers.