A new species of the fish genus Ilyodon is described from San Juan Tacámbaro river, Michoacán, México 19° 10' 42" N, 1010 20' 45" W, We used 129 specimens representing I. whitei, 60 of r furcidells and 84 ofthe new species for our analyses_ These included samples ofbolh sexes, The new speeies is distinguished [rom r whitei and l. furcidens by ils strongly eonvex cephalie profile, the size and disposition of the pores of the laleral line of the preorbital, the thinner caudal pedunde, Íls strongly bifid tooth and the form and size of neural prezygapophyses of caudal vertebrae