Azathioprine is an imidazole derivative of 6-mercaptopurine and is well known for its role in T and B lymphocyteinhibition. These properties have made it useful in the treatment of organ transplant rejection, rheumatoid arthritis,and severe psoriasis. We studied the effects of low-dose azathioprine and acitretin combined therapy in 3 cases ofrefractory psoriasis. The patients had previously been treated with other systemic and topical therapies. Althoughthey had received partial and temporary benefits, they were not controlled effectively. These patients weresubsequently treated with azathioprine and acitretin. Azathioprine treatment (50-100 mg/day) in combination withacitretin (10 mg/day) showed marked improvement of recalcitrant psoriasis. There were no noticeable major sideeffects associated with this course of treatment. In conclusion, some cases of recalcitrant psoriasis may be effectivelyand safely controlled using low-dose of azathioprine and acitretin combined therapy.