We entrapped lipase in electrospun poly(vinyl alcohol) fibers of approximately I Pm in diameter and evaluated the transesterification activity by converting (s)-glycidol to glycidyl n-butyrate with vinyl n-butyrate. The initial transesterification rate of the entrapped lipase was 5.2-fold faster than that of non-treated lipase. The fibrous membrane could be used as a component of a flow-through reactor for continuous transesterification.