Chitosan-wrapped multi-walled carbon nanotubes/Doxorubicin (CS-MWCNTs/DOX) nanoparticles were used to control the delivery of doxorubicin into Ehrlich ascites carcinoma-bearing mice (EAC-bearing mice). Both CS-MWCNTS/DOX and free DOX were intraperitoneally injected into EAC-bearing mice. Tumor killing, animal survival, and changes in biochemical and apoptotic markers associated with cell growth or cell death were all assessed in vivo. The results demonstrated that treatment of EAC-bearing mice with loaded and free DOX increased the animals' life span (49.3±2.5 and 40±3) compared to 17 days for the untreated tumor-bearing mice. Treating with CS-MWCNTs/DOX significantly reduced cardiac enzymes compared to treating with free DOX. Furthermore, BAX and Caspase-3 levels as apoptotic markers were elevated in liver tissue homogenate, whereas Bcl-2 levels as anti-apoptotic markers decreased. So, necrosis and apoptosis were the suggested mechanisms of tumor killing. Finally, the prepared drug delivery system succeeded in treating the tumor by reducing the free drug side effects.