Transnasal fiberscopy is a procedure wherby a flexible fiberoptic endoscope is inserted via one of the nasal passage to exmine nasal, pharyngeal, velopharyngeal anatomy and functions. Since it's introduction in the late 1960s, the transnasal fiberscope has become an indispensable diagnostic and therapeutic instrument for the clinical management of voice disordered patients. It has been reported that wide variations exist in normal laryngeal structure and function. However, there is still a paucity of endoscopically-derived data on normal laryngeal activity. Without such normative data, there is a risk of measurement error and unreliable observer judgement during transnasal fiberscopic laryngeal evaluation of patients with voice disorders. Furthermore, to ensure that the procedure is performed with minimal discomfort, a topical anaesthetic is applied, but it has been hypothesized that transnasal fiberscope itself and the associated topical anaesthesia may alter vocal behavior. To ensure that transnasal fiberscopic interpretation of normal and disordered laryngeal are error-free, the effects of the procedure itself and the effects of the anaesthesia on phonation need to be delineated. The present study aimed to investigate possible acoustic and perceptual changes on phonation under four experimental conditions-a) pre-anaesthetic, b) transnasal fiberscopr only, c) anaesthetic only and d) anaesthetic and transnasal fiberscope.