Subclinical joint involvement in psoriasis has been found with bone scintigraphy. In this study, 35 of 50 (70%) patients with psoriasis without clinical arthropathy had joint involvement on bone scintigraphy. Patients with positive bone scans were started on oral methotrexate, and 20 patients who completed treatment had repeat bone scintigraphy. Of the 20 patients, the post-treatment bone scans found that 12 (60%) had involvement of different sets of joints, 1 (5%) had no change and 7 (35%) patients had fewer joints involved. We suggest that subclinical joint involvement in psoriasis can be detected with bone scintigraphy, and that it is fleeting in nature. A certain degree of treatment-induced regression of joint involvement on bone scintigraphy may be possible.