Psoriasis is a chronic, papulosquamous condition that affects up to 2% of the U.S. population. Approximately 50% of patients with psoriasis have involvement of the scalp. This was a multicentre, randomized, vehicle-controlled, double-masked and parallel-group study. The aim was to evaluate the efficacy and safety of clobetasol propionate shampoo, 0.05% versus its corresponding vehicle in subjects aged 12 years and older with moderate to severe scalp psoriasis over a treatment period of 4 weeks. Recurrence of scalp psoriasis was assessed during a two week follow-up period. A total of 142 subjects were treated. Results after 4 weeks demonstrated that clobetasol propionate shampoo, 0.05% was with a similar safety profile significantly more effective than its vehicle. The novel short contact shampoo formulation of clobetasol propionate is convenient and efficacious and minimizes systemic exposure while being efficient, safe and well-tolerated in the treatment of moderate to severe scalp psoriasis.