Gastric carcinoma following operation for benign peptic ulcer disease has been considered rare but nine patients have been seen during the past five years. All were male patients, the average time interval from prior ulcer operation to development of cancer was 17 years, but was as short as ten years. The symptoms of cancer are vague and the diagnosis is often delayed. Fiberoptic endoscopy with biopsy of suspicious areas is the most accurate diagnostic approach. Resection of the tumor is indicated if feasible. The poor prognosis of this malignancy is documented. The evidence is reviewed that the creation of achlorhydria with bile reflux increases the risk of development of gastric carcinoma. All patients who undergo peptic ulcer operation require careful long-term follow-up. Vague gastrointestinal symptoms occurring ten years or more after peptic ulcer operation require full evaluation to exclude the presence of gastric cancer.