Liposomes and monoclonal antibodies are used as drug carriers for the optimal delivery of pharmacologic agents. However, they present disadvantages that led us to develop a new model of drug carriers: the nanoerythrosomes. Nanoerythrosomes are vesicles prepared by the extrusion of red blood cell ghosts, the average diameter of these vesicles is 0.1 micron. Daunorubicin was covalently linked to nanoerythrosomes and the cytotoxicity of daunorubicin conjugated to nanoerythrosomes was assessed on P388D1 cell line. The results indicated that the cytotoxicity of conjugated daunorubicin was as high as the free daunorubicin. Daunorubicin--nanoerythrosome conjugates had a higher antineoplastic activity than the free drug on CDF1 leukemia tumors. These results indicate that nonoerythrosomes could be potentially used as drug carriers.