Abstract. Two cases of nasal pythiosis are reported in horses from the semi-arid region of northeastern Brazil. From received 830 equine samples, 156 (18.79%) of which were diagnosed with pythiosis. Of these, two horses (1.28%), a male and a female adult crossbreed , had lesions in the nasal cavity. Both horses had access to water reservoirs. Clinically, they had swelling in the rhinofacial region and a serosanguineous nasal discharge. Macroscopically, in case 1, the lesion affected the nasal vestibule, extending to the alar cartilage and nasal septum. In case 2, the lesion extended through the turbinates and the meatuses of the nasal cavity, as well as the ethmoid region. In both cases, the lesions were characterized by having a yellowegrey granular surface with cavitations of different sizes containing coral-like masses of necrotic tissue (kunkers). Histologically, multi-focal necrotizing eosinophilic rhinitis associated with hyphae (2e8 mm) similar to Pythium insidiosum were observed. In case 2, the lesions extended to the muscle, cartilage and bone adjacent to the nasal cavity and lungs. The diagnosis was confirmed by immunohistochemistry. It is concluded that nasal pythiosis occurs sporadically in horses in the semi-arid region of northeastern Brazil where cutaneous pythiosis is prevalent.