Changes in the olfactory ability are one of early symptoms of developing neurodegenerative diseases, especially Parkinson’s disease and Alzheimer’s disease. In a healthy population olfactory function is characterized by independence from an intelligence quotient and various cognitive functions, e.g., memory. The peak of the olfactory ability falls between 20 and 40 years of age. In the geriatric population the worsening of the olfactory ability is found. Because of it, the knowledge on differences between the changes associated with physiological aging and the symptoms indicating pathological changes in the brain is of clinical importance. In this article, neuroanatomical structures of the olfactory tract and their involutionary changes, which may contribute to age-related olfactory deterioration, are discussed. Data are presented on the frequency of olfactory dysfunction occurrence, sex differences in the olfactory ability, and characteristics of its worsening among the elderly. Furthermore, age-related changes in odor memory are reviewed. The authors suggest that the main criterion allowing for differentiation between a physiological and pathological smell loss is awareness/unawareness of the deficit in this domain.