The present work is the first of a series in which the Pyramidellidae of the Red Sea will be studied. We start with the tribe Chrysallidini, which includes the genera Helodiamea (2 species), Strioturbonilla (1), Parthenina (12), Pyrgulina (20), Chrysallida (1), Costabieta (1), Miralda (4), Oscilla (10), Pseudoscilla (1) and Babella (6). In total, there are 58 species, of which 34 are new to science. One species had a preoccupied name and is renamed. Whenever we were able to photograph the type material of the different species, such photos are shown, and the new species are studied, described and represented through micrographs made with the scanning electron microscope.