This study demonstrates the use of chemically functionalized single-walled carbon nanotubes (SWNTs) for drug delivery in cancer treatment. SWNTs, conjugated with paclitaxel (PTX), a widely used chemotherapy drug, exhibit enhanced tumor suppression efficacy compared to the clinical formulation Taxol® in a murine 4T1 breast cancer model. The SWNT-PTX conjugate is water-soluble, biocompatible, and exhibits prolonged blood circulation due to the high hydrophobicity of PTX, which reduces the biological inertness of the PEGylated SWNTs. This results in higher tumor uptake of PTX through the enhanced permeability and retention (EPR) effect. The SWNT-PTX formulation also shows lower toxicity to normal organs, as evidenced by lower levels of PTX in the reticuloendothelial system (RES) organs and rapid excretion of dissociated PTX through the biliary pathway. The study highlights the potential of SWNTs as a promising nano-platform for cancer therapy with high treatment efficacy and minimal side effects.This study demonstrates the use of chemically functionalized single-walled carbon nanotubes (SWNTs) for drug delivery in cancer treatment. SWNTs, conjugated with paclitaxel (PTX), a widely used chemotherapy drug, exhibit enhanced tumor suppression efficacy compared to the clinical formulation Taxol® in a murine 4T1 breast cancer model. The SWNT-PTX conjugate is water-soluble, biocompatible, and exhibits prolonged blood circulation due to the high hydrophobicity of PTX, which reduces the biological inertness of the PEGylated SWNTs. This results in higher tumor uptake of PTX through the enhanced permeability and retention (EPR) effect. The SWNT-PTX formulation also shows lower toxicity to normal organs, as evidenced by lower levels of PTX in the reticuloendothelial system (RES) organs and rapid excretion of dissociated PTX through the biliary pathway. The study highlights the potential of SWNTs as a promising nano-platform for cancer therapy with high treatment efficacy and minimal side effects.