The Smell Identification is an olfactory test that is administered by specialty physicians and clinics. This commercially available test consists of odorants and each sample odorant has alternative answers, from which the patient must choose one. The test is read to the patient and is then scored by the examiner. It is very reliable (test-retest r=0.94) and accurate test of olfactory function that has been heralded as being akin to the eye chart in vision. This test provides an absolute index of smell loss (anosmia; mild, moderate, or severe microsmia), as well as index for detecting malingering and percentile rank of the examinee based upon norms in men and women spanning the entire age range. It has been shown to have excellent short (r = +0.95) and long term (r = +0.92) test-retest reliability. This test has been used in many published scientific studies, and is the standard means for assessing olfactory function. It is also especially useful for examining olfactory ability in young (ages 5-9) and elderly patients, for which age-related norms have been carefully developed. This test has achieved widespread acceptance as a standard measure of olfactory ability. In conjunction with the odor identification and threshold tests, this test can provide a very quantitative index of olfactory ability. Moreover, the Smell Identification Test is being used as a examination test in the diagnosis of Alzheimer’s and Parkinson’s Disease.