This is an analysis of 32 patients who received long continuous corticosteroid drug due to some diseases. Patients were collected from June 1976 to March 1980. Blood cortisol leve1, variation of diurnal rhythm and side effects were studied. The Result as follows: 1) Side effects were observed in 24 patients(75%) and most common complaint was obesity. 2) Diurnal rhythm analysed by Doe's method shows abnormal diurnal rhythm is 21 out 32(66%) 3) Mean durations of therapy of abnormal diurnal rhythm were 55.7¡¾4.4 months and 43.9¡¾7.0 months respectively which shows statistically significant difference. 4) Mean cortisol value of steroid treated patients were lower than normal. 5) Reverse diurnal rhythm was 4 out of 21 patients. 6) 8 A.M. cortisol value is lower than 2 times of 8 P.M. in all patients who showed abnormal diurnal rhythm except one.