The Nail Psoriasis Severity Index (NAPSI) has been designed and successfully implemented to grade severity of psoriatic nail disease. Moreover, the utilization of the NAPSI score and a modified version of this severity index score as an instrument to monitor response to therapy has been recently documented in the medical literature .This open study involves thirty-six patients with moderate to severe nail psoriasis treated with low-dose acitretin from January 2005 to January 2007.Acitretin was given at the dosage of 0.2 to 0.3 mg/Kg/day for 6 months. Laboratory investigations and clinical evaluation, which included photographic record and scoring of NAPSI and modified NAPSI, were performed every 2 months. Investigator evaluation was performed using a 0 (no improvement) to 3 (cleared or almost cleared) score Treatment satisfaction by patients and tolerability were assessed at each visit. All patients were followed for at least 6 months after the end of treatment.