New species assignable to the formerly monotypic genus Echinopsyllus (Copepoda, Harpacticoida, Ancorabolidae) are described from the continental slope of Campos Basin off Brazil in the south-western Atlantic. Echinopsyllus brasiliensis sp. nov., Echinopsyllus nogueirae sp. nov., and Echinopsyllus grohmannae sp. nov. differ from Echinopsyllus normani Sars, 1909 in the cephalothorax having two instead of three pairs of lateral processes, first pair of dorsal cephalothoracic processes being smaller than second pair, second pair of dorsal cephalothoracic processes branched, and segmentation and setation of the swimming legs. The discovery of new species of Echinopsyllus extends the distributional range of the genus to the southern hemisphere and is further evidence for the formerly unexpected wide genus-level distribution of Ancorabolidae in the world's oceans. The phylogenetic position of Echinopsyllus within Ancorabolinae is discussed. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156, 52–78.