Necrotizing granulomatous inflammation of the upper respiratory tract is one of the hallmarks of Wegener's granulomatosis (WG), which may explain the reason for olfactory dysfunction in WG. However, a systematic analysis using modem olfactory testing tools has not been performed and potential causes of dysfunction at different levels of olfactory information processing remain obscure so far. In this study a group of 76 WG-patients was examined with sniffin'sticks screening 12, odour threshold (T)/discrimination (D)/identification (I) TDI-score, active anterior rhinomanometry and a standardized questionnaire for olfactory function. WG-patients were aware of their olfactory dysfunction, as proven by psychophysiological test results. An altered olfactory function was significantly correlated to local administration of mupirocin and to the time interval between first diagnosis and study entry. None of the other variables had a statistical significant effect on the olfactory dysfunction.