To reach a consensus for reporting complications related to cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Reporting the adverse events related to CRS + HIPEC is not standardized yet. Post-operative complications can be divided in two categories: the effects of surgical manipulation per se and the toxic effects of the heated intraoperative chemotherapy. Additive and/or synergistic effects also exist. Different centers have published their experience with regard to the complications associated with the procedure. Various classification systems have been used which makes a temptative comparison of the different techniques and results almost impossible. An effort was made here to review the existing major classification systems: The Bozzetti classification, the Clavien classification (and two proposed modifications from Feldman et al. and Elias et al.) and the Common terminology criteria for adverse events (CTCAE) version 3.0 of the National Institute of Health (NIH) criteria. A related document was sent to an international panel of experts. The CTCAE was adopted by the panel of experts as the unique classification system to be used for reporting complications related to CRS + HIPEC.