A virus is a nanoscaled biomolecular substance composed of genes, protecting capsid proteins, and envelopes. The nanoscale dimensions and surface functionalities of virions have been exploited to attract and assemble inorganic and organic materials to produce functional nanomaterials with large surface areas. Genetic modifications of virus capsid proteins lead to the selective deposition and controlled growth of inorganic substances producing organized virus-based hybrid materials. Due to these properties, viruses hold promise for development as platforms for the creation of hybrid materials with multiple functionalities. This article reviews the characteristics of commonly used viruses and their fabrication into virus-based hybrid materials that have been applied in engineering applications such as nanowires and catalysts. Biotechnol. Bioeng. 2012;109: 16–30. © 2011 Wiley Periodicals, Inc.