Background Complete surgical resection of gastric cancer is potentially curative, but long-term survival is poor. Methods Patients with histologically proven adenocarcinorna of the stomach of stages IB, II, IIIA and B, or IV (T4N2MO) and treated with potentially curative surgery were randomly assigned to follow-up alone or to intravenous treatment with four cycles (repeated every 21 days) of PELF (cisplatin [40 mg/m(2), on days 1 and 5], epirubicin [30 mg/m(2), days 1 and 5], L-leucovorin [100 mg/m(2), days 1-4], and 5-fluorouracil [300 mg/m(2), days 1-41 in a hospital setting. Frequencies and severity of adverse events were determined. Overall survival (OS) and disease-free survival (DFS) were compared between the treatment arms using Kaplan-Meier analysis and a Cox proportional hazards regression model. All statistical tests were two-sided. Results From January 1995 through September 2000, 258 patients were randomly assigned to chemotherapy (n = 130) or surgery alone (n = 128). Patient characteristics were well balanced between the two arms. Among those who received chemotherapy, grade 3 or 4 toxic effects including vomiting, mucositis, and diarrhea were experienced by 21.1%, 8.4%, and 11.8% of patients, respectively. Leucopenia, anemia, and thrombocytopenia of grade 3 or 4 were experienced by 20.3%, 3.3%, and 4.2% of patients, respectively. After a median follow-up of 72.8 months, 128 patients (49.6%) experienced recurrence and 139 (53.9%) deaths were observed, one toxicity-related. Relative to treatment with surgery alone, adjuvant chemotherapy did not increase disease-free survival (hazard ratio [HR] of recurrence = 0.92; 95% confidence interval [CI] 0.66 to 1.27) or overall survival (HR of death = 0.90; 95% Cl = 0.64 to 1.26). Conclusions Our results failed to provide proof of an effect of adjuvant chemotherapy with PELF on overall survival or disease-free survival. The estimated effect of chemotherapy (10% reduction in the hazard of death or relapse) is modest and consistent with the results of meta-analyses of adjuvant chemotherapy without platinum agents.