A cladistic analysis of the Blephariceromorpha (here including the Nymphomyiidae, Deuterophlebiidae and Blephariceridae) and related Diptera provides a test of the phylogenetic hypotheses of Rohdendorf (1964, 1974), Hennig (1973), Wood & Borkent (1989) and Courtney (1990a). In particular, monophyly of the Blephariceroidea and Blephariceromorpha (sensu Wood & Borkent), and their relationship to other Diptera, is tested. Evaluation of larval, pupal and adult characters supports the hypothesis of Wood & Borkent, as modified by Courtney. Four larval features suggest that the Blephariceromorpha + Psychodomorpha form a monophyletic group, although an alternate hypothesis predicting that the Blephariceromorpha is the sister group of the Psychodomorpha + (Ptychopteromorpha + Culicomorpha), is discussed. Monophyly of the Blephariceromorpha (Nymphomyioidea + Blephariceroidea) is supported by one adult and five larval characters. Monophyly of the Blephariceroidea (Deuterophlebiidae + Blephariceridae) is supported by thirteen synapotypies, including features of the larva (six), pupa (three) and adult (four). Nineteen, nineteen and nine hypothesized synapotypies support monophyly of the Nymphomyiidae, Deuterophlebiidae and Blephariceridae, respectively.