Clobetasol propionate (CP) shampoo 0.05% is an efficacious and safe treatment for scalp psoriasis. The aim of this double-blind, randomized, placebo-controlled study was to determine if CP shampoo is suitable for long-term disease control. Participants with moderate to severe scalp psoriasis (global severity score [GSS] of 3 or 4 on a scale of 0 [clear] to 5 [very severe]) first received once daily CP shampoo treatment for up to 4 weeks. Responders were subsequently randomized to receive the CP shampoo or vehicle twice weekly maintenance regimen for up to 6 months. When relapse occurred (defined as GSS > 2), participants resumed once daily CP shampoo treatment; when symptoms diminished (GSS < or = 2), they readopted the twice weekly maintenance regimen. At all visits significantly more participants treated with CP shampoo did not relapse compared with participants treated with vehicle (P < .001). Only approximately one-third of participants treated with vehicle remained relapse free at 1 month, while this rate was observed approximately 3.5 months later (4.5 months after baseline of maintenance phase) in the CP shampoo group. After 6 months 31.1% (33/106) of participants in the CP shampoo group were still relapse free versus 8.1% (9/111) of participants in the vehicle group. There was no greater incidence of skin atrophy, telangiectasia, or hypothalamic-pituitary-adrenal (HPA) axis suppression in the CP shampoo group compared with the vehicle group. Clobetasol propionate shampoo is efficacious and safe for acute management and long-term maintenance of moderate to severe scalp psoriasis.