Transesterification of arbutin and undecylenic acid vinyl ester was catalyzed by alkaline protease, Bioprase, in dimethylformamide to get arbutin derivative having undecylenic acid at 6-position of glucose moiety, 6-O-undecylenoyl p-hydroxyphenyl beta-D-glucopyranoside. The reaction rate increased with increase of arbutin concentration, and when its concentration was 0.9 M, the conversion rate was more than 90% under addition of 2 M undecylenic acid vinyl ester. The obtained arbutin ester significantly suppressed melanin production in murine B16 melanoma cells. (C) 2007 Elsevier Ltd. All rights reserved.