Considering the aerial surveillance and reconnaissance applications, the use of infrared detectors gains importance. In this scene, one of the primary issues that should be decided happens to be the operating range of the detectors. Namely, the midwave and longwave ranges which are usually defined in the ranges of 3-5 and 8-12 mu m, respectively, come into the picture as viable alternatives. In this work, the basic properties of infrared detectors operating in midwave and longwave regions are presented and then they are compared in terms of certain performance criteria. The study is concluded by a general evaluation.