Our main aim in the present investigation was to assess and compare the in vitro and in vivo cancer targeting propensity of doxorubicin (DOX) loaded folic acid (FA) and estrone (ES) anchored PEGylated multiwalled carbon nanotubes (MWCNTs) employing tumor bearing Balb/c mice. The DOX was loaded into the developed functionalized MWCNTs after proper characterization using dialysis diffusion method. The in vitro, ex vivo, and in vivo studies were performed on the MCF-7 cell line for assessment of the cancer targeting propensity. Both qualitative and quantitative cell uptake studies indicated the preferential higher uptake of estrone anchored nanotube formulation compared to other formulations and free DOX owing to the overexpression of estrogen receptors (ERs) on human breast MCF-7 cells. Similarly, the pharmacokinetic and increased antitumor activities also confirmed the elevated cancer targeting propensity of the estrone and folic acid anchored MWCNT formulations. The DOX/ES-PEG-MWCNTs has also shown significantly longer survival span (43 days) than free DOX (18 days) and control group (12 days). Present outcomes from the ex vivo and in vivo studies are deemed to be of great scientific value and shall assist targeted drug delivery formulation scientists for selection of the targeting moieties in the treatment of human breast cancer.