The Cephalocarid, Sandersiella chilenica sp. nov. from Coliumo Bay, Central Chile ( 36º 32' S lat.; 72º56' W long) is described. The new species was collected at only one bottom station (station 4) in a grid of 11 stations sampled monthly during 1982-83, with predominating fractions of fine sand, silt and clay. Four other species of the genus are so far known (Sandersiella acuminata Shiino 1965, and S.kikuchii Shimomura & Akiyama, 2008, from Japan, S. calmani Hessler & Sanders 1973 from off Perú, and S. bathyalis Hessler & Sanders 1973, from Walvis Ridge, and off Namibia, SE Atlantic, and off Santos, Brazil). S. chilenica sp. nov, is differentiated from each of these by its comparatively greater maximal length, its shorter and proportionally thicker caudal rami, and the orbicular form of the second podomere of the exopod in thoracopod 6. A SEM study of the external morphology has allowed us to propose the differentiation of setae and other external cuticular body structures following the classifications proposed for Crustacea in general, although possible analogies or homologies need yet to be clarified.