A new ankylosaur Hungarosaurus tormai gen. et sp. nov. from the Upper Cretaceous (Santonian) Csehbánya Formation of the Bakony Mountains, western Hungary is described here. Among the four discovered specimens of this new armored dinosaur the best preserved is the most complete ankylosaur presently known from the Upper Cretaceous of Europe. Although many cranial characters of Hungarosaurus are not determinable, a preliminary phylogenetic analysis places Hungarosaurus in the Nodosauridae as a basal nodosaurid. Hungarosaurus is clearly distinguishable from Struthiosaurus on the basis of the dorsoventrally wide quadratojugal, the presence of bony protuberances on the quadratojugal and postorbital, the robust mandibular quadrate condyle, and the interpterygoid vacuity. The analysis suggests that Hungarosaurus appears to be more derived than Struthiosaurus, but more primitive than the North American Silvisaurus, Sauropelta, and Pawpawsaurus.