This report covers the period from 1 July 1984 to 30 June 1987. The ephemerides that have been published during this period have made use of the new system of astronomical constants adopted at the XVIth General Assembly of the lAU in Grenoble. Yet some difficulties have arisen because of the lack of catalogues or maps of the heavens established for the epoch J2000.0. This is awkward for observers of comets and minor planets and, for that reason, Commission 20 decided, at the New Delhi meeting of lAU that there would be a gradual introduction of the J2000.0 system as far as those bodies are concerned.