Dirofilariasis is caused by filarial nematodes (roundworms) of the genus Dirofilaria. Dirofilariasis of the oral mucosa is very rare. Herein, we report a case of a 79-year-old man who had a slowly growing infiltrative mass in the right buccal space. Histopathologic examination showed an inflammatory infiltrate with eosinophilia, histiocytes, and small organisms (0.2-0.3 mm). Digital images were sent to the Centers for Disease Control and Prevention, which identified the parasite as a nematode in the genus Dirofilaria. It appeared to be dead and degenerating, but external, fine longitudinal cuticular ridges and the presence of tall muscle cells were diagnostic. Thus, Dirofilaria, despite its rarity, should be considered in the differential diagnosis of tumor-like lesions in the buccal mucosa.