A dataset of 120 characters of syrphoid adult morphology was compiled. The taxon set comprises 48 species representing 43 genera of Syrphidae and two taxa of Pipunculidae (Nephrocerus lapponicus and Pipunculus sp.). The taxon set was chosen to comprise elements of all the assumed main clades of Syrphoidea. Platypezidae (Agathomyia falleni) was used as outgroup. The characters and character state assignments are discussed for each character. Fifty figures of characters and characters states are presented, either as drawings or as SEM images. A wealth of new characters was discovered in the ultrastructure of different types of setae and sensilla. The patterns of vestiture, including the microtrichia, are important and widely used. Also the characters of both male and female postabdomens constitute an important source. We discuss homologies of particular characters across the Syrphoidea. The parsimony analysis resulted in one most parsimonious tree of length 606 steps. Pipunculidae and Syrphidae are monophyletic. Contrary to all earlier hypotheses Neoascia + Sphegina appear as the sister group to all other Syrphidae. The Microdontinae (including Spheginobaccha), Nausigaster and the rest of Syrphidae are resolved in a trichotomy. The main group of Syrphidae is composed of two large clades roughly corresponding to the Eristalinae in the traditional sense, and (Callicerini + ((Rhingiini + Volucellini) + (Pipizini + Syrphinae))). The Eumerus group plus Syritta and Ceriana is the sister of that clade.