Iatrogenic Cushing's syndrome (ICS) is usually related to prolonged and/or high-dose oral or parenteral steroid use. Psoriasis vulgaris (PV) is chronic inflammatory disease and characterized by periods of attack and remission. Topical steroid (TS) is the first choice of treatment for localized and mild PV. The development of systemic side effects of the steroids is usually not observed after TS application. But the risk of developing ICS still exists. In the literature, there are a few adult cases who developed ICS and subsequent adrenal insufficiency associated with TS. In this article, a male patient with PV developing ICS and secondary adrenal insufficiency after treatment of TS for 12 years is presented.