124 Rhesus monkeys (Macaca Mulatta) were caught in the Taihang Mountain region, a high incidence area of human esophageal cancer in Northern China, in January 1989. Among them, two monkeys died of esophageal carcinoma in 1990. Case 1, a male monkey about 6.5 years old and weighing 14.5 kg, had symptoms of salivation, vomiting and dysphagia in February 1990. The symptoms became gradually more serious and died in March 1990. Postmortem examination revealed a huge tumor in the distal segment of esophagus, causing severe stricture of the organ. The tumor was classified as medullary type and histopathologically diagnosed as a well differentiated squamous cell carcinoma, with metastases to mediastinum and lymph nodes of right gastric group. Case 2, a female monkey about 11-year-old and weighing 10.0 kg, showed loss of appetite, tiredness, somnolence, coughing and vomiting in September and died in December 1990. Autopsy revealed an annular tumor involving the whole circumference of lower portion of the esophagus. The tumor was of ulcerative type and diagnosed as a well differentiated squamous cell carcinoma. The symptoms and pathological changes of the two monkeys showed high similarity to esophageal cancer in humans. We believe that the present findings would provide important leads for further study to clarify the etiology and pathogenesis of human esophageal cancer in this high incidence area of esophageal cancer.