Homologous blood transfusion in the cancer patient is dangerous because of an apparent immunodepressive action. Even a program of pre-deposit and isovolemic hemodilution, for reasons of immediacy and patient conditions, is often not feasible. Likewise, the intraoperative recovery of blood, although used by some, does not prevent the possible reinfusion of suspended neoplastic cells. A system that eliminates tumor cells could enable the recovery of blood in cancer patients in non-septic operative sites. A system that seems to correspond to these requisites has been set up by inserting two filters for the elimination of leucocytes from erythrocyte concentrates into a cell separator that is normally used in clinical practice. Laboratory studies, using immunohistochemical identification of tumor cells cultivated in vitro, have demonstrated the absence of contaminating cells in blood available for reinfusion.