OutbreakID® was developed for physicians and public health professionals who stand on the frontlines as the key agents for the early detection of outbreaks. OutbreakID® covers potential outbreaks caused by exposures to toxins, chemicals, and infectious agents. It covers 201 diseases (156 infectious diseases), including nearly every disease listed in the Control of Communicable Diseases Manual. The value of the application lies in its scope and its easy-to-navigate design. It includes chemical and biological weapons, emerging infectious diseases, foodborne illness, occupational diseases, zoonoses, and arthropod-borne infections. Users can query the database of 201 diseases (156 infectious diseases) by 135 signs & symptoms, 17 syndromes, 102 jobs, 101 activities, 39 epidemiological factors, and 16 regions of the world. OutbreakID®, now in PDA format, gives physicians and public health professionals all the information at their fingertips for the early detection of outbreaks.