Objectives: To evaluate the efficacy and safety of adapalene 0.1% benzoyl peroxide 2.5% gel in women aged 25 years or older via subgroup analysis of existing Phase 2 and 3 study data. Methods: Meta-analysis of pooled data from three multicenter, randomized, double-blind, vehicle-controlled, parallel-group, clinical trials compared results of treatment with either adapalene 0.1% benzoyl peroxide 2.5% gel or vehicle gel in adult females and teen-aged females. Efficacy assessments included investigator's global assessment and median percent change in acne lesions. Safety assessments included skin tolerability and adverse events. Results: Two hundred fifty-four adult females and 488 teen-aged females were included in the analyses, and baseline characteristics were comparable between subjects receiving adapalene 0.1% benzoyl peroxide 2.5% or vehicle. Both adult females and teen-aged females in the adapalene 0.1% benzoyl peroxide 2.5% arm were significantly more often rated clear/almost clear compared with those in the vehicle arm at Weeks 8 (P=0.016) and 12 (P<0.001); at endpoint, success was achieved in 39.2 percent with adapalene 0.1% benzoyl peroxide 2.5% and 18.5 percent with vehicle. Comparison of the amount of difference between active and vehicle reductions in investigator's global assessment showed that efficacy was similar for adult females versus teen-aged females (20.7% vs. 19.9%, respectively). Adapalene 0.1% benzoyl peroxide 2.5% had a rapid onset of action, with statistically significant reductions in all acne lesion types versus vehicle observed by Week 1. Adapalene 0.1% benzoyl peroxide 2.5% was safe and well-tolerated by adult females with a tolerability profile consistent with that seen in teen-aged females. Conclusions: The once-daily fixed-dose combination product adapalene 0.1% benzoyl peroxide 2.5% is an efficacious, safe, and well-tolerated treatment for adult female acne, with a profile similar to that in teen-aged females.