Cyclosporine has been mainly used for the prevention of rejection after kidney transplantation. Recently, it has been also tried for the treatment of skin diseases including atopic dermatitis. There have been several reports that ketoconazole can increase blood cyclosporine level if both drugs are taken together and its mechanism is thought to be related to hepatic cytochrome P-450. As cyclosporine is still expensive drug and major organ of side effect of ketoconazole is liver not kidney as cyclosporine. we think combination treatment is justifable. We have successfully treated 2 cases of atopic dermatitis with combination treatment and effective blood levels of cyclosporine were observed without major side effect.