A comparatice study was conducted on two groups of patients with the generalized severe form of myasthenia gravis. The first group of 20 patients received oral daily doses of 60-100 mg of prednisone prior to thymectomy. The control group of 20 were submitted to surgery without prior corticosteroid treatment. The study included statistical analysis of the clinical results and surgical complications for both groups. The author concluded that the use of steroids preoperatively is beneficial.