Quantum dots (QDs) are semiconducting materials which have a wide array of applications starting from semiconducting devices, in humidity and pressure sensors and in medical imaging including cancer therapy. In the present study, cadmium telluride (CdTe) QDs were synthesized by a biological method using yeast cells, Saccharomyces cerevisiae in modified Czapek's medium. QDs were characterized by transmission electron microscopy and X-ray diffraction. Cancer cells were treated with 2, 4, 8 and 16 μM concentrations of CdTe QDs for 24 h. The anti-proliferative activity was determined by using MTT assay, by evaluating the production of reactive oxygen species (ROS), and also by nuclear apoptosis and cell cycle analysis using a flow cytometer against human prostate carcinoma cell line PC-3. The size of the CdTe QDs was approximately 2 nm. In vitro anti-proliferative study showed that CdTe QDs induced cell death and nuclear apoptosis in a dosedependent manner. CdTe QDs induced significant increase in ROS level in PC-3 cells which was dose-dependent. Moreover, CdTe also arrested growth of PC-3 cells in the G2/M phase of the cell cycle. This study elucidates the apoptotic activity of CdTe QDs on prostate carcinoma which could provide useful insights to researchers for its clinical application.