Wegener's Granulomatosis (WG) is a rare, multi-system disease of unknown aetiology. The disease is characterised by necrotizing granulomas and vasculitis of the upper and lower respiratory tracts and kidneys. The sinonasal region may be the first area to manifest this systemic condition. If the disease is diagnosed early and treated appropriately, involvement of the lungs and kidneys may be averted. Left untreated, the disease may prove rapidly fatal. A low threshold of clinical suspicion must be maintained. We report a case, of a middle aged patient who presented with unilateral sinusitis secondary to a large obstructive nasal mass. Anti neutrophil cytoplasmic antibody (ANCA) titres helped confirm the diagnosis of WG. Unilateral sinusitis with a nasal mass, is a very unusual presentation of WG, and emphasises the importance of a low threshold of suspicion for patients presenting with atypical sinonasal symptoms.