An eco-friendly reaction for the preparation of thioglycosides has been developed using an ionic liquid as the solvent. Thioglycosides were obtained in excellent yields on treatment of per-O-acetylated sugar derivatives with thiols in the presence of boron trifluoride diethyl etherate in [Bmim][BF4] as solvent at 20C. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file. © Taylor & Francis Group, LLC.