Microemulsion-based hydrogel formulation containing 0.05% methoxsalen with a suitable viscosity for topical administration were successfully formulated by swelling 1.5% Carbopol 934 in microemulsion system. Microemulsion formulation serves as efficient promoters of the methoxsalen localization into the skin. The enhanced skin accumulation of methoxsalen could help significantly to optimize the targeting of the drug without a concomitant increase of the systemic side effects.The microemulsion is a very good vehicle for topical delivery of methoxsalen.