ABSTRACTAll trilobite species and species in comparative nomenclature described from Great Britain and Ireland are listed where possible in an appropriate modern genus together with a selected synonymy; the type specimens, stratigraphic horizon and original or type locality are given. Salter's Monograph of the British trilobites is reviewed and revised determinations are presented for the plates, text-figures and nomenclatural acts within Salter's text. Lectotypes have been selected where appropriate. Comments are made on the validity of other lectotype selections. The generic nameBettonolithus(forBettoniaWhittard, 1956), the specific namesAcadoparadoxides (Baltoparadoxides) quadrispinosus, Dipleura salteri, Ogyginus? sedgwickiandStenopareia trippi, and the subspecific nameParadoxides davidis avalonensisare proposed as replacements.