Natural products continued to be the treasure trove for the discovery of anticancer drugs. The activity of certain natural products significantly increased with the use of novel drug delivery systems (DDS). Aiming to improve the activity of a natural cytotoxic agent; Sesamol, it was loaded onto cadmium sulfide (CdS) quantum dots (QDs) modified chitosan (CTS). The formed complex Sesamol-CdS@CTS was characterized using X-ray diffraction, UV-Vis absorption spectroscopy, thermogravimetric analysis, dynamic light scattering, Zeta-potential, Fourier transform infrared spectroscopy, fluorescence emission, high resolution transmission electron microscopy, and selected area electron diffraction. The concentration effect of Cd2+ and chitosan on the particle size of CdS QDs was investigated. The cytotoxic activity assay showed that Sesamol-CdS@CTS was more effective against cancer cells compared to the drug alone. The results showed that the half maximal inhibitory concentration values (IC50) of CdS@CTS, Sesamol, and Sesamol-CdS@CTS were 1730 ± 54, 495 ± 16.4, and 117 ± 3.2 μg/mL, respectively. Our results indicated that CdS@CTS exhibited high loading efficiency, and can be used for drug delivery.