Nasal eucoleosis is an uncommonly diagnosed parasitic infection in domestic dogs. Depending on the parasite load, dogs with Eucoleus boehmi may exhibit mild upper respiratory signs such as sneezing and nasal discharge or may not exhibit any clinical signs. The present study describes the case of a 6-year-old male dog, presented with reverse sneezing of 2 months' duration and bilateral nasal serous discharge. The patient had been taking prednisolone for years due to an immune mediated arthritis of the carpal joint. Physical examination, complete blood count, serum chemistry and thoracic radiography were unremarkable. A computed tomography scan of the nasal cavity was compatible with bilateral chronic rhinitis of unknown aetiology. Further investigation by rhinoscopy revealed diffuse erythematous mucosae with several white and serpentine-shaped worms on the turbinates' surface. Morphological identification of the worms collected in situ was performed, revealing filiform nematodes (15-30 mm in length) containing several bipolar plugged and barrel-shaped eggs in their medial segment. The eggs contained a multicellular embryo, a pitted surface and measured 54-60 μm long by 30-35 μm wide. Morphological and morphometric characteristics were consistent with E. boehmi. Treatment with imidacloprid/moxidectin spot-on formulation along with preventing measures to minimise reinfection were prescribed and successfully achieved, as confirmed by negative faecal examinations. To the best of the authors' knowledge, this represents the first report of E. boehmi infection in a dog from Portugal. Nasal eucoleosis appears to be underestimated and should be considered as a differential diagnosis in canids suffering from upper respiratory distress.