At present there is no established standard chemotherapy for advanced gastric cancer. Combination regimens have yielded response rates at times exceeding 50% but with no improvement in survival compared to single agents. This study examined the role of 5-fluorouracil and high-dose levamisole in a phase II setting using survival as the main endpoint. Patients with advanced carcinomas of the stomach or gastroesophageal junction were treated with 5-fluorouracil, 450 mg/m2 IV days 1 to 5, and levamisole, 100 mg/m2 orally three times daily on days 1 to 3, and 50 mg/m2 tid days 4 to 5 every 5 weeks. To allow more rapid accrual and to study a population that more accurately reflects the makeup of patients treated in clinical practice, patients with both measurable and nonmeasurable disease were entered in this study. Two of fifteen (13%) patients with measurable disease experienced a partial response to treatment. The adjusted 1-year survival rate for the 44 patients entered was 29.6%, which is similar to the historical 1-year survival of 30% observed in a group of nearly 400 patients treated in prior North Central Cancer Treatment Group studies. This regimen offers no improvement in therapeutic activity for advanced gastric cancer. This study design, however, allows rapid screening of phase II regimens in patients who would usually be candidates for phase III trials.