A revised checklist of the British and Irish Heloridae and Proctotrupidae (Proctotrupoidea) substantially updates the previous comprehensive checklist, dating from 1978. Country level data (i.e. occurrence in England, Scotland, Wales, Ireland and the Isle of Man) is reported where known. A total of three Heloridae and 39 Proctotrupidae (including only certainly recorded species) represents a 27% increase in the British list since 1978. Most species are still poorly known and there has been a dearth of taxonomic and faunistic work on the British and Irish fauna.