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The phylogenetic relationships and systematic position of members of the families Macroderoididae and Ochetosomatidae have long been controversial. In the present work, phylogenetic affinities of 2 ochetosomatid species (Ochetosoma kansense, Dasymetra nicolli) and 4 macroderoidid species (Macroderoides typicus, M. spinifer, Glypthelmins quieta, G. pennsylvanicus) are examined on the basis of partial 28S rDNA sequences. Sequences of 19 other species belonging to 9 families of the suborder Plagiorchiata were used in the phylogenetic analyses and species of two members of Troglotrematidae were used as outgroups. The analyses demonstrate that Glypthelmins does not belong to Macroderoididae but instead forms a strongly supported sister group to other family-level branches that comprise a polytomy within Plagiorchioidea. According to our results, Macroderoididae and Ochetosomatidae form branches independent of Plagiorchiidae, a family into which both groups have been placed previously by several authors. Furthermore, Ochetosomatidae demonstrates close affinity to Telorchiidae and the genus Haplometra, which has been considered by some authors as a member of Macroderoididae, belongs to Plagiorchiidae. These results suggest the need for further studies focusing on examination of the phylogeny and systematics of a wide variety of plagiorchioidean genera, particularly problematic genera presently belonging to Macroderoididae, Plagiorchiidae and Ochetosomatidae.