OBJECTIVES The aim of this research is to define development principles of medical devices for nasal drug delivery and their effect on therapeutic outcome on the basis of detailed insight on anatomy, physiology and aerodynamics of nasal cavity, possibilities of nasal drug delivery and advantages/disadvantages of existing medical devices. Hypotheses are as follows: Nasal administration can be used to deliver drugs for either local or systemic effect. In addition, nasal drug administration can result in direct nose to brain delivery. Anatomy, physiology and aerodynamics of nasal cavity represent obstacles for deposition of nasally administered drugs. Characteristics of formulation and medical device impact therapeutic outcome. MATERIAL AND METHODS The literature search was performed electronically; based on the PubMed scientific database search, an overview of anatomical and physiological characteristics of nasal cavity was presented, as well as critical review and explanation of advantages and limitations which could affect the performance of nasally administered drugs. In addition, a review of medical devices for nasal delivery, from the very begining to the cutting-edge technologies, and their impact on therapeutical outcome was also presented. Guidelines of European Medicines Agency (EMA) and US Food And Drug Administration (FDA) related to pharmaceutical quality of inhalation and nasal products and bioavailability and bioequivalence studies for nasal aerosolos and nasal sprays for local action were thoroughly studied. RESULTS Development of innovative drug formulations enables delivery of nasally administered drug to the site of action in appropriate concentration and duration. Literature reports indicate the importance of concurrent development of medical devices for nasal drug delivery whose final characteristics also affect deposition/residence time/bioavailability of nasally administered drug and therapeutic outcome. CONCLUSION Pharmaceutical form and mode of application affect the drug deposition site and residence time within the nasal cavity. Therefore, current investigations are directed towards innovative medical devices and new concepts of aerosol generation and delivery, aiming to increase bioavailability of nasally administered drugs and to improve therapeutic outcome.