Polyacrylonitrile (PAN), a well-known polymer with good stability and mechanical properties, has been widely used in producing carbon nanofibers (CNFs) as these have attracted much recent attention due to their excellent characteristics, such as spinnability, environmentally benign nature and commercial viability. Among the various precursors to produce CNFs, PAN has been extensively studied due to its high carbon yield and flexibility for tailoring the structure of the final CNFs as well as the ease of obtaining stabilized products due to the formation of a ladder structure via nitrile polymerization. In view of this, they have applications in areas such as electronics, tissue engineering, membrane filtration and high performance composites. This review presents various combinations of PAN and PANbased precursors in producing CNFs from the PAN homopolymer or its modified precursors, copolymers, blends and various composites. Various modifications of PAN and their future prospects in different scientific and technological disciplines are addressed. (C) 2011 Elsevier Ltd. All rights reserved.