Psoriasis is primarily an inherited inflammatory skin disease, it is characterized by erythemato-squamous lesions that usually involve elbows, knees and the scalp. Oral manifestations are rare in psoriasis, infact, oral psoriasis involves 2% of psoriatic patients and usually it is observed with the onset of cutaneous lesions and progresses with them. Differential diagnosis should be done for Reiter's syndrome, leukoplakia and geographic tongue. The authors describe a case of tongue psoriasis without cutaneous lesions.