Onychomycosis is a recalcitrant fungal nail infection. Topical antifungal agents may be preferred over systemic agents due to lack of systemic adverse events.We investigated the efficacy and safety of topical terbinafine 10% solution (MOB-015) for the treatment of distal and lateral subungual onychomycosis (DSO).In a multi-center, double-blind, phase III, North American study subjects with mild to moderate DSO involving 20-60% of at least one great toenail were randomized to once daily application of MOB-015 or matching vehicle for 48 weeks. The primary and secondary efficacy variables were complete and mycological cure, respectively. Safety evaluations were performed.At week 52, the mycological cure (negative culture and KOH) rate in the MOB-015 and vehicle groups were 69.9% and 27.7%, respectively (P< 0.001). Complete cure (0% clinical disease involvement and mycological cure) was achieved in 4.5% and 0% subjects, respectively (P=0.0195). Subjects with at least one adverse event (AE) leading to discontinuation were 2.8% in the MOB-015 and 4.2% in the vehicle group.Follow-up period after end of treatment may not be sufficient to accurately reflect cure in DSO.MOB-015 is a treatment option for onychomycosis with an AE profile similar to vehicle.