A new fossil Brachycera (Diptera), Cratomyia macrorrhyncha gen. n. & sp. n. is described from the Santana Formation, Lower Cretaceous, situated on the Araripe Basin (Northeastern Brazil). Its remarkable features are the large body size, very long proboscis, antenna with multi-articled flagellum, robust thorax and abdomen, and wing characters like the abbreviated costal vein, distally forked veins R4+5 and M1+2, strongly arched M1, and closed cells m3 and cup. The new genus and species does not reasonably fit in any of the existing families and a new family, Cratomyiidae is proposed. The systematic position of the family is discussed. Reasons are given for not including it in the following higher taxa of Brachycera: Xylophagomorpha, Tabanomorpha, Vermileonomorpha, Asilomorpha, and Eremoneura. The Cratomyiidae are included in Stratiomyomorpha as the sister-group of Xylomyidae + Stratiomyidae, above the origin of Pantophthalmidae.