To increase the stability of ascoryl palmitate (AP), ethosome, which is hydrated liquid crystalline vesicle, was used to entrap it. AP concentration was measured directly by HPLC with an UV-visible detector. The test samples were stored at 40℃ for nineteen days. The recovery of AP was increased with AP content but it was decreased with cholesterol (Chol) content. Thermal stability AP entrapped in ethosome were enhanced compared to that in standard solution.