There is a lack of an internationally accepted standardised clinical definition for postoperative ileus (POI). This has made it difficult to estimate incidence and identify risk factors and has compromised external validity of clinical trials. To clarify terminology of POI and propose concise, clinically quantifiable definitions. A systematic review extracted definitions from randomised trials published between 1996 and 2011 investigating POI after abdominal surgery. This was followed by a global survey seeking opinions of those who have published in the field. Definitions were extracted from 52 identified trials. Responses were received in the survey from 45 of 118 corresponding authors. Data were amalgamated to synthesise the following definitions: postoperative ileus (POI) "interval from surgery until passage of flatus/stool AND tolerance of an oral diet"; prolonged POI "two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of flatus over 24 h, distension, radiologic confirmation occurring on or after day 4 postoperatively without prior resolution of POI"; recurrent POI "two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of flatus over 24 h, distension, radiologic confirmation, occurring after apparent resolution of POI". Concordance of the latter two definitions with survey responses were ≥75 %. We have proposed standardised endpoints for use in future studies to facilitate objective comparison of competing interventions.