Gastric ulcers developed in four patients with myasthenia gravis while they were receiving therapy for their myasthenia. A conservative regimen healed the ulcers in two patients, and two required surgical procedures. A combination of etiologic factors seemed to be responsible for the development of ulceration in these patients. It is desirable to attempt a medical, rather than surgical, cure of the ulcers in such patients; however, if proper precautions are taken, complications of surgical treatment need not occur.