Twenty-five previously untreated patients with advanced adenocarcinoma of the upper gastrointestinal tract were treated with a combination of carboplatin and vinblastine. Two partial responses (duration three months and six months) were seen among 22 evaluable patients. Myelosuppression was the most common toxicity and was generally mild. The 8% response rate, (95% confidence interval 2 to 24%) observed in this study indicated that carboplatin-vinblastine has only modest activity in adenocarcinoma of the upper gastrointestinal tract. Although less toxic, this regimen appears to be less effective than previously reported cisplatin-containing regimens in adenocarcinoma of the upper GI tract.