Nanofiber composite materials play an important role in tissue engineering (TE) and regenerative medicine, mimicking the structure and properties of the extracellular matrix at nanoscale. They serve as scaffolds for cells, as carriers for various biomolecules (e.g., drugs, genes, and soluble factors), and as injectable biomaterials in TE and regenerative medicine. Clinical and preclinical studies of nanofiber composite materials have recently emerged to further develop therapeutic applications of these materials. Topics of these studies range from tissue regeneration and wound healing to biosensing and monitoring, demonstrating the great promise of nanofiber composites for a wide variety of clinical applications. This book chapter describes the characteristics and applications of nanofiber composite materials in clinical and preclinical studies. Results of relevant research are highlighted and potential research directions are discussed. © 2017 Elsevier Ltd. All rights reserved.