The present statistical investigation was undertaken in order to establish what is the most significant out of various side-effects of glucocorticoids(GC) in Japan. From the viewpoint of mortality, side-effects of GC can be classified into two groups:"Major" and"Minor" side-effects."Minor side-effects" denotes moonface, obesity, hypertrichosis, anorexia, polyphagia, headache, hypertension, hypercholesterolemia and glucosuria, etc., which by themselves scarcely affect the mortality. On the other hand,"major side-effects" may contribute to the mortality or tend to leave various severe disturbances. The frequency of major side-effects much lower than that of minor ones, may still reach 5 to 20% of the patients treated with GC(Smyth et al., 1959; Katsu et al., 1963). The results of our survey on the side-effect of glucocorticoid by means of questionnaires sent to clinical department in various medical schools in japan is summarized in the present report. METHODS The questionnaires concerning the major side-effects were sent to 344 clinical department of internal medicine, surgery, orthopedics, pediatrics and dermatology, in medical schools all over Japan. The answers were obtained from 102 departments. Amog 194 cases thus collected(107 males and 87 femals) 15 showed at least one side-effect, giving the total frequency of side-effect of 212. The age distribution ranging from 1 month to 79 years old is shown in Table 1. Table 1. Age distribution