The advantage of nanomaterials in the biomedical field can be explored through the use of nanofibers designed using biocompatible and biodegradable polymers. Owing to their versatility and unique properties, nanofibers have attracted the biomedical community for their applications in tissue engineering, drug delivery, gene therapy, and cell therapy. For tissue engineering applications, nanofibers can be explored as scaffolds due to their potential to mimic the native extracellular matrix (ECM) collagen structure of the cell niche/microenvironment. In natural systems, the ECM not only provides the topographical cues but also offers various biochemical signals to regulate the cell's fate and functions. Therefore, to completely mimic the natural microenvironment, these nanofibrous scaffolds needs to provide a critical signaling environment that can regulate the resident cell behavior and destiny. Composite nanofibers reinforced with various biomolecules like growth factors, cytokines, small molecules, etc. have recently emerged as a solution for completely mimicking the natural microenvironment. The unique advantages of nanofibers such as high surface area, interconnected pores, porosity, etc. have been explored for its use in the delivery of drug molecules, genes (RNA, DNA), and living cells, for various biomedical applications. This chapter essentially describes the various ways of forming biomolecule composite nanofibers, associated characterization techniques, and different release mechanisms with the focus on composite nanofibers and nanoparticles in biomolecular delivery. For the benefit of readers, authors have briefly explained the applications of composite nanofibers as well as nanoparticles for the biomolecule delivery in different biomedical fields along with their clinical status and their future perspectives. © 2017 Elsevier Ltd. All rights reserved.