Personalized medicine has recently emerged as promising alternatives to conventional treatment modalities to overcome the underlying genetic variations in an individual’s drug response. Nanotheranostics, an interdisciplinary field of both nanotechnology and theranostics, has gained immense importance from this perspective. A nanotheranostic agent comprises three essential components, namely, imaging, therapeutic, and a carrier agent. For this, several materials are developed and designed to integrate multiple modalities in a single nanoplatform. In this chapter, various materials used for the development nanotheranostic agents will be discussed in detail with some of the recent developments in the field using supporting literature. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.