>One-dimensional inorganic semiconductor nanowires form an attractive class of materials for different sensing applications as a result of their distinctive size- and shape-dependent physical properties. Numerous synthesis and characterization methods have been developed in recent years to realize high-quality semiconductor nanowires with controllable dimensions, shape, and morphology. Additionally, a growing number of novel chemical and biological sensors with high sensitivity and selectivity have been developed based on semiconductor nanowires. In this review, several main approaches in synthesizing semiconductor nanowires, i.e., the vapor phase, solution phase, and template-based syntheses, are discussed. These include the vapor-liquid-solid (VLS), vapor-solid (VS), solution-liquid-solid (HS), supercritical fluid-liquid-solid (SFLS), oriented attachment, and the hard and soft templates-assisted growth mechanisms. Next, the optical properties of these nanowires, in particular the UV-vis absorption, photoluminescence, and Raman properties, are explored. Recent advances in the chemical and biological sensing applications of semiconductor nanowires are then presented. For instance, the applications of semiconductor nanowires as NH3, H-2, NO2, and other chemical and gas sensors as well as DNA, miRNA, glucose, uric acid, cysteine, and other biological sensors are briefly mentioned. Finally, this review summarizes and projects the future development of this field. (C) 2013 Elsevier Ltd. All rights reserved.