Despite the fact that clinical otolaryngologists are often presented with complaints of olfactory dysfunction, they have limited means to diagnose these problems. A major reason has been the lack of a clinically-useful and reliable quantitative test of olfactory function. Recent work at our Clinical Research Center has resulted in the development of such a test. This test--the University of Pennsylvania Smell Identification Test (UPSIT)--can be self-administered and uses microencapsulated odorants which are released by scratching standardized odor-impregnated test booklets. As indicated in this paper, studies have demonstrated that the UPSIT can identify most malingerers and is sensitive to age, gender, smoking habits, and a wide variety of olfactory disorders. A description of this new test, along with some of its applications, is presented.