A 9 yr old female spayed Labrador retriever presented for progressive dyspnea. Inspiratory stridor and inspiratory and expiratory dyspnea were present, consistent with an upper airway obstruction. A laryngeal exam revealed severe thickening of the arytenoid cartilages and masses associated with the arytenoids. A tracheostomy tube was placed, and the masses were biopsied. Histopathology showed pyogranulomatous inflammation secondary to Blastomyces dermatitidis. The dog was initially treated with amphotericin B and terbinafine in the hospital until the airway obstruction resolved and the tracheostomy tube could be removed. The dog experienced complete recovery after long-term treatment with itraconazole and terbinafine. This is the first report of laryngeal obstruction secondary to primary laryngeal blastomycosis in a dog. Blastomycosis should be considered for cases of obstructive laryngeal disease, and a good outcome can be achieved with antifungal treatment.