To analyze the phylogenetic relationships of the genus Pseudocrangonyx within the superfamily Crangonyctoidea, we sequenced a partial LSU rDNA gene from four species (six specimens). The monophyly of Pseudocrangonyx and its affinity to Crymostygius were strongly supported by four reconstruction methods: neighbor-joining, minimum evolution, maximum-likelihood, and Bayesian inference. Current geographical distributions of the taxa studied and their phylogenetic relationships established in our study suggest that members of Pseudocrangonyctidae and Crymostygius diverged from a common Crangonyx-like ancestor in the Arctic Basin region of the northern hemisphere.