Infectious diseases account for millions of sufferings and deaths in both developing as well as developed countries with a substantial economic loss. Massive increase in world population and international travel has facilitated their spread from one part of the world to other areas, making them one of the most significant global health risks. Furthermore, detection of bioterrorism agents in water, food and environmental samples as well traveler's baggage is a great challenge of the time for security purpose. Prevention strategies against infectious agents demand rapid and accurate detection and identification of the causative agents with highest sensitivity which should be equally available in different parts of the globe. Similarly, rapid and early diagnosis of infectious diseases has always been indispensable for their prompt cure and management, which has stimulated scientists to develop highly sophisticated techniques over centuries and the efforts continue unabated. Conventional diagnostic techniques are time consuming, tedious, expensive, less sensitive, and unsuitable for field situations. Nanodiagnostic assays have been promising for early, sensitive, point-of-care and cost-effective detection of microbial agents. There has been an explosive research in this area of science in last two decades yielding highly fascinating results. This review highlights some of the advancements made in the field of nanotechnology based assays for microbial detection since 2005 along with providing the basic understanding. © 2013 Elsevier B.V. All rights reserved.