Three new species and a new genus of majoid crabs from deep waters in the eastern Pacific are described and illustrated using morphological and molecular data. A new species of inachoidid, Collodes anartius sp. n. is described from Peru, which resembles C. tenuirostris Rathbun, 1893, in the general appearance of the carapace, but is distinguished by the details of tubercles on the carapace and thoracic sternum, proportions of the pereopod articles, and bathymetric distribution. A new epialtid, Nibilia machala sp. n., is described from Ecuador; Nibilia A Milne-Edwards, 1878 has, until now, been considered to be monotypic, occurring only in the western Atlantic. This new species, from the eastern Pacific, closely resembles N. antilocapra (Stimpson, 1871) in the general morphology, but can... be distinguished by the number of spines on the carapace and pereopods. Another epialtid, Solinca aulix gen. n. et sp. n, is establish for material collected from Ecuador and Peru, and can be easily identified from other taxa by the presence of a deep furrow between the very inflated branchial regions.