The new sauropod dinosaur Tastavinsaurus sanzi, gen. et sp. nov., from the early Aptian of Spain is described. The holotype is a partially articulated skeleton of an adult individual recovered from the Arsis-1 site in Peñarroya de Tastavins (Teruel) at the base of the marine Xert Formation. It is one of the most complete and best-preserved sauropod dinosaur skeletons from the European Early Cretaceous. The fossil remains comprise the three caudalmost thoracic vertebrae, part of a fourth, nine thoracic rib fragments, sacrum, 25 caudal vertebrae, 21 chevrons, both ilia, pubes, ischia and femora, right tibia, right fibula, six metatarsals, and seven pedal phalanges (including four unguals). The new taxon is defined by 19 autapomorphies. In our cladistic analysis, Tastavinsaurus is the sister-taxon of the North American Venenosaurus within Titanosauriformes, which includes the Brachiosauridae, Somphospondyli, and Titanosauria. The new taxon provides new information about the diversity of non-brachiosaurid titanosauriforms during the Early Cretaceous in Europe and paleobiogeographic relationships between Europe and North America.