A 54-year-old woman developed psoriasis on the plantar surface of her feet after 2 weeks of thalidomide 100 mg daily for the treatment of multiple IgG myeloma. She did not have any previous history of psoriasis. Thalidomide was immediately stopped and topical treatment with calcipotriol ointment and β-methasone valerate was started. Psoriasis disappeared completely after 2 weeks of topical therapy. This is the first case of de novo psoriasis in a patient with multiple myeloma under treatment with thalidomide. Our observation provides further evidence of the potential paradoxical effect of thalidomide on tumour necrosis factor-α production.