Background: Onychomycosis is a fungal infection of the nail apparatus that can be challenging to treat due to the modest efficacy of existing antifungal therapies and a high rate of relapse and recurrence. Objectives: To investigate the efficacy and safety of efinaconazole 10% solution in pooled Phase III clinical trial participants with mild to moderate onychomycosis. Methods: Phase III clinical trials data from NCT01008033 and NCT01007708 were pooled. Efficacy analysis for the primary and secondary outcome variables was conducted using the mITT population and analysed using Cochran-Mantel-Haenszel tests. Subgroup analysis was conducted for prognostic factors that may affect drug efficacy. Safety analysis was conducted on all recipients of a single drug dose. Results: Efinaconazole 10% nail solution was superior to vehicle for all primary and secondary outcome measures assessed. Complete cure was 18.5% vs 4.7% P<0.001 [mlTTl and mycological cure was 56.3% vs 16.6%, P<0.001 [mlTTI. Complete or almost complete cure and treatment success were achieved in 277% and 47.2% compared to 7.9% and 18.2% with vehicle, respectively (P<0.001 ImlTTI). In all subgroups, efinaconazole 10% solution had statistically higher cures rates compared to vehicle. Higher complete cure rates were observed in women and individuals with mild disease (≤33% involvement), but not in any other subgroup assessed. Treatment associated adverse events in the efinaconazole 10% solution group were similar to vehicle and limited to local site reactions (2%). Conclusions: The findings from this pooled analysis suggest that efinaconazole 10% solution may become the preferred topical agent for mild to moderate onychomycosis. Copyright © 2014 Journal of Drugs in Dermatology.