The first edition of this directory was published almost 20 years ago. Since then, numerous new species have been described, some genera and families have been revised, and new synonymies and updated keys have been published. These changes have all been incorporated into this second, amended, English edition of Répertoire mondial des Crustacés Copépodes des eaux intérieures, tome 1: Calanoida. The contents are organized as in the previous edition. The references cited in the taxonomic part are given in alphabetical order, and the abbreviations of the references follow the ISO-4 standards (ISDS, 1985 and following years). The scientific index includes the synonyms in Roman characters, which allows the reader to follow the trail of any citation to its present valid name. For each genus, the typespecies is given first and is marked by an asterisk; the order followed for the other species is chronological. For each species, a synonymy is given, followed by other specifying citations or references on morphology, physiology, biology, or ecology of the species; distribution is also given. The 8 families treated are: Aetideidae, Clausocalanidae, Centropagidae, Pseudodiaptomidae, Acartiidae, Sulcanidae, Temoridae, and Diaptomidae (the most widely distributed family in inland waters). All species described from 1898 until 2000 are included. This is a definite reference work for all those involved in copepod research.