Introduction: The olfaction contributes significantly to the quality of life, allowing the interaction with the environment through the perception of odors. The quality and intensity of such perception depends upon the anatomic and functional state of the nasal epithelium and peripheral and central nervous systems. Objective: In this study, we review the olfactory anatomy as well as the main methods for the investigation of olfactory function. Only recently, it was possible to have to have the availability of various exams, classified as subjective, semi-subjective and objective ones, and we point out their main advantages and disadvantages. Conclusions: We have to consider that the early detection of olfactory disorders might lead to treatment strategies to minimize the progression of the disease.