A case-control study was conducted to evaluate the role of dietary selenium (Se) intake and the selenium nutritional status in the course of psoriasis. The cases studied were 30 psoriatic patients with a history of the disease no longer than 10 months and 29 psoriatics with the disease lasting at least 3 years, 24 other dermatological patients and 14 healthy subjects constituted 2 control groups matched to cases studied by sex and age. Se dietary intake was calculated from 24-hours dietary recall and Se status was assessed with plasma Se level as well as plasma and erythrocyte GSH-Px activity. Dietary Se intake was found to be correlated to erythrocyte GSH-Px (r = 0.50, p < 0.05). The selenium nutritional status seemed to be insufficient, especially in females with psoriasis of no longer than 10 months' duration and males with long-lasting psoriasis. In these males plasma and erythrocyte GSH-Px activity were inversely correlated to the severity of the disease (r = -0.64 and r = -0.41, p < 0.05, respectively). The results obtained suggest that Se dietary intake could be one of the contributing factors in the pathogenesis and course of psoriasis. Further studies are needed to explore this relationship.