Nanodiamonds have attracted great attentions lately for their superb physical/chemical properties and promising bio/medical applications. This versatile material in its nanoscale exhibits little cytotoxicity in the cellular level and is considered to be most biocompatible among carbon derivatives. Its surface can be easily modified; so, various functional groups can be generated to allow conjugation of various biomolecules of interest for applications. Nanodiamonds thus provide a convenient platform for bio and medical applications. Among the various useful characteristics of nanodiamods, their spectroscopic properties, such as Raman and fluorescence, are ideal for use as a biocompatible marker to probe the biointeractions. In this chapter, the possibilities of using nanodiamond as a probe for biolabeling/cellular surgery are discussed. For this purpose, functionalization and characterization methods of nanodiamond surfaces are developed. The interaction of proteins with targeted bioobjects are investigated in various models to test the feasibility of ND to use as nano-bio-probe. Further applications using the developed nano-bio-probe as a surgical tool in the nano scale is also proposed. This developed methods of using nanodiamond as a nano-bio-probe will provide a biocompatible biolabel in bio and medical applications.