Cis-diamminedichloroplatinum (DDP) was administered at 100 mg/m2 intravenously bolus with every 3-week schedule in patients with measurable and nonmeasurable incurable gastric cancer. Twenty patients were treated, 12 with measurable and 8 with nonmeasurable disease. Four of the 12 (33%) patients with measurable lesions had objective remissions. One remission was complete, lasting 60+ weeks. Patients with nonmeasurable disease were not eligible for response evaluation; they were followed for toxicity and survival. Hematologic, renal, and gastrointestinal toxicities were similar to those reported in other patient populations receiving DDP. Neurotoxicity proved to be dose limiting in two patients. The median survival was 38+ weeks for responders, 24 weeks for all patients, and 13 weeks for those 8 patients with nonmeasurable disease. DDP should be considered an active drug against gastric cancer. A better understanding of the dose response relationship for DDP in gastric cancer is necessary before the best dose and schedule can be chosen for DDP in combination with other active agents.