Angelica gigas is one of the most widely used herbal medicines in Asia. Root extract of Angelica gigas is known to have anti-oxidant activity and skin whitening effect. The aim of this study was to prepare microemulsion system of root extracts of Angelica gigas for topical delivery. Microemulsion was successfully prepared by using MCT (medium chain triglyceride) as an oil phase, Labrasol as a surfactant, and the mixture of propyleneglycol and phosphatidylcholine (4 : 1) as a cosurfactant. In vitro and in vivo skin permeation and deposition of decursin, as a marker, was determined using hairless mouse. Microemulsion significantly increased the in vitro skin permeation of decursin for up to 12 hours and was significantly higher than the control (water). Moreover, microemulsion formulation showed significantly higher skin deposition of decursin compared to the control in both in vitro and in vivo studies. Thus, microemulsion could be a useful vehicle for topical application of root extracts of Angelica gigas.