Arterial infusion therapy was applied to 77 patients with 18 unresectable, 29 non-curatively resected and 20 recurrent gastric cancers. 5-fluorouracil (5-FU) was administered by arterial continuous infusion, and adriamycin (ADM) and mitomycin C (MMC) by bolus infusion. The clinical effectiveness of each was evaluated. One-year cumulative survival rate of primary case by Kaplan-Meier method was 19.2%, and that of recurrent gastric cancer was 5.3%. Median survival time of primary case was 6.5 months, showing prolongation compared with recurrent ones. Also, in primary cases, the arterial infusion therapy was more effective in non-curatively resected cases than in unresectable ones. Two of the patients are now alive and another is apparently free of tumor and the remaining one had a recurrence. Continuous arterial 5-FU infusion and ADM low-dose intermittent bolus infusion chemotherapy (AF therapy) were considered an effective supportive treatment without any serious side effects for unresectable, noncuratively resected and recurrent gastric cancer.