This study attempts to uncover major success factors for outsourcing a portion of hotel affairs. Object of the case study is four deluxe hotels in Seoul metropolitan area. Due to lack of existing knowledge on the topic, a multiple-case study was employed as a research method. Followings were found as major success factors for outsourcing. The selection of appropriate vendor, managerial skill in charge of hotel management, the enhancement of service quality, and the partnership between hotels and vendors. The shortcut of successful outsourcing might be achieved by effective application of the above-mentioned factors as well as by improving existing problems, and lessening the gap in critical success factors being considered importantly by hotels and vendors.