Combined oral retinoid (RO 10.9359) and PUVA therapy were given to 107 patients with psoriasis, 9 of whom had psoriatic arthropathy. Treatment was started with the retinoid at a dose of 1 mg/kg day and PUVA therapy added after 2 weeks. No other treatment was given. In 100 patients the combined therapy achieved clearing of the lesions, including scalp lesions, in a shorter time and with less total joules/cm2 than a group treated by PUVA alone. The remaining 7 patients were not responding to PUVA alone but achieved clearing when the retinoid was added. Five patients out of 9 with psoriatic arthropathy responded to the combined therapy. Predictable mild side-effects from the retinoid were encountered. The teratogenic risk of retinoid therapy is emphasized. The value of combined retinoid-PUVA therapy in psoriasis is discussed.