Eptatretus aceroi, new species, is described from one specimen captured on the upper continental slope in ColombianCaribbean waters at 705 m depth. The species can be distinguished from all congeners by having five gill apertures, 3/2multicuspid teeth in the outer and inner tooth rows, respectively, an extremely slender body with the depth at thevertical through the pharyngocutaneous aperture 2.4% of the total length, and by having a total of 174 slime pores, thehighest count in the genus. The species is compared with the other western Atlantic five-gilled species of Eptatretus.