Bats are often difficult to observe in their natural habitat. Because of their nocturnal, acoustically oriented behavior and their tendency to group together in inaccessible crevices, researchers have been limited in their ability to obtain even the most basic data on their ecology and behavior. A number of strategies have been used to quantify the behavior of bats in their natural environment. Since 1978, when Slusher first introduced military night vision applications at the Entomological Society of America symposium, there have been few applications of similar techniques in the study of bats. In the study of bats, infrared imaging provides these advantages: it is portable; self-contained; non- invasive; and can provide a permanent recording of bat location and behavior which may be used for subsequent laboratory analysis and comparison, and is especially effective where stop and slow motion video permits observation of transient occurrences and allows for sampling techniques. In the current study, big brown bats, Eptesicus fuscus, were first observed in a laboratory setting to determine their responses to the presence of the IR imager. Following the determination of its non- invasive nature, big brown bats were located and observed in natural surroundings. The data obtained showed that infrared imaging has potential application in counting emerging bats; counting or estimating size of nesting colonies or area occupied in situ; location of bats roosting in inaccessible sites; non-invasive behavior investigation such as following movement of individuals in the roost; diagnosing infection sites in injured bats; image processing for both graphic presentation and analysis of data.