This is a worldwide catalogue of the family Merlucciidae. Two subfamilies, Macruroninae and Merlucciinae, are recognized comprising four genera, Lyconodes, Lyconus, Macruronus and Merluccius, and 18 species. Dichotomous keys are provided in the systematics chapter, enabling the identification of the hakes to the species level. Subfamilies and genera are also defined. The species are arranged in alphabetical order under each subfamily and genus to which they belong. The scientific name appears in bold at the head of each genus and species description, followed by the author, year of first description, and publication. Existing synonyms and FAO common names in English, French and Spanish are also provided. For each species there is an illustration followed by ten sections: description or diagnosis with differential characters; additional information; geographical distribution; habitat and biology; size; fisheries; fishery statistics; state of resources; local names, if any; and bibliographical references (author and year). The review is completed by a series of colour plates showing details of different elements (heads, otoliths, hyomandibulars, urohyals) for a quick and efficient diagnosis of the genera and species of Lyconus, Macruronus and Merluccius.