We present a case of esophageal ulcerations caused by alendronate (Fosamax), a recently marketed medication. The patient presented with a chief complaint of retrosternal pain and severe odynophagia of 5 days duration. She was taking prednisone 10 mg and azathioprine 100 mg p.o. q.d. for systemic lupus erythematosus. To prevent osteoporosis, she was started on alendronate 10 mg q.d. 2 wk before her symptoms started. Endoscopy of the upper GI tract revealed two deep, large ulcers at the gastroesophageal junction. Multiple biopsy specimens revealed necroinflammatory debris and acute esophagitis. However, no organisms were identified, and the result of her HIV test (ELISA) was negative. Alendronate was discontinued, and her symptoms resolved completely in 1 wk. Follow-up endoscopy performed 4 wk later revealed complete healing of the ulcers.