A double-blind, randomized, vehicle-controlled, parallel-group trial was performed to compare the efficacy and tolerability of tazarotene 0.1% gel and vehicle gel in 31 patients with fingernail psoriasis. Patients were randomized to receive tazarotene or vehicle gel, which they applied each evening for up to 24 weeks to 2 target fingernails, one under occlusion and one unoccluded. The tazarotene treatment resulted in a significantly greater reduction in onycholysis in occluded nails (P < or = .05 at weeks 4 and 12) and a significantly greater reduction in onycholysis in nonoccluded nails (P < or = .05 at week 24). Tazarotene also resulted in a significantly greater reduction in pitting in occluded nails (P < or = .05 at week 24). There were no other significant between-group differences in pitting, subungual hyperkeratosis, leukonychia, nail plate crumbling/loss, splinter hemorrhage, or nail growth rate. Tazarotene 0.1% gel was well tolerated with only 5 of the 21 tazarotene-treated patients reporting a treatment-related adverse event (all mild or moderate). In conclusion, tazarotene 0.1% gel can significantly reduce onycholysis (in occluded and nonoccluded nails) and pitting (in occluded nails) and is well tolerated in the treatment of nail psoriasis.