The mainstay of treatment of chronic rhinosinusitis is through the administration of topical nasal drugs. The delivery and intranasal distribution of these is therefore of potential clinical significance. Until there is progress in the nasal drug distribution assessment methodology, it will be difficult to improve topical nasal drug delivery, which is known to be suboptimal in many ways. This study reviews intranasal drug delivery assessment methods, the present knowledge and explores future directions for research.