AbstractSt Kilda is a remote but exceptionally interesting archipelago in the North Atlantic. Its rich bryoflora has not previously been documented. A list of the mosses and liverworts from the main island, Hirta, is given, including published records and additional species recorded on separate visits by the authors in 1959 and 1991. A total of 160 species is reported, comprising 56 liverworts and 104 mosses. The richness and phytogeography of the bryoflora of Hirta is discussed in relation to climate, ecology and vegetation history and is compared with similar studies on other islands.