We present a case of long-standing unilateral cacosmia in a healthy 67-year-old man due to maxillary fungal infestation. Treatment with septoplasty had been attempted 10 years prior but no further investigation or management undertaken and symptoms continued. Subsequent MRI scan revealed significant opacification of the left maxillary sinus. This was readily amenable to treatment by balloon sinuplasty. This yielded viscous grey mucus which grew Scedosporium apiospermum. The case highlights the need for careful investigation of olfactory symptoms, including blood tests to exclude systemic causes, endoscopy and imaging where indicated.