This paper looks into knowledge that is 'wasted' in organisations, that is existing relevant knowledge that is not (re)used in business operations. Against the backdrop of today's business environment, a lack of knowledge application is not only costly but also dangerous. Therefore, the purpose of this paper is to review research on knowledge reuse (waste) in organisations to identify our current body of knowledge and gaps in the field justifying further research activities. In order to do so, the study consists of a systematic review of 52 refereed empirical articles on knowledge reuse in organisations. The topic seems to be a promising field for intensive research and offers a variety of future research avenues. Some ideas for future research are proposed in this study.