Abstract: Nanodiamond (ND) represents a unique allotrope of the carbon family. Its physical and chemical properties afford ND useful applications from material point of view. Recently ND has been showing great potential in bio/medical applications for bio imaging and drug delivery owing to its superb spectroscopic properties. The fluorescence properties of ND arisen from defects and admixtures in the crystal lattice or on the surfaces. This provides a stable and non-photobleaching fluorescence for imaging. ND’s surface can be functionalized to form complexes with bio-molecules of interest. This renders ND the possibilities of drug conjugation and delivery. Combining these advantages, image-guided drug delivery systems for preclinical applications can be realized. In this talk I will share various examples that has been realized in the cellular and animal models. However conventional 2D cell culture model does not represent 3D structural of tissues and tumors, the 2D cellular models offer poor access to the efficiency of drug delivery. To address this, we developed a 3D multicellular tumor spheroid (MCTS) cellular model to demonstrate the possibility of using ND for drug delivery and to evaluate the efficacy of the drug conjugate of ND-Drug in cancer therapy.