A partial skeleton of an elasmosaur (Plesiosauria; Elasmosauridae) was collected from a farm field located in southern Bryan County of south central Oklahoma. The subsurface geology is the Lewisville Member of the Woodbine Formation, (Cenomanian, early Late Cretaceous). Thirty cervical, seventeen dorsal, four sacral, twenty-five caudal vertebrae, intact sacral ribs, miscellaneous vertebral and rib fragments and an incomplete pelvic girdle were recovered by Henry Brigman and staff and volunteers from the Sam Noble Oklahoma Museum of Natural History (SNOMNH), Norman, Oklahoma. Prior to this discovery, only two isolated plesiosaur vertebra where known from Oklahoma. Both are from the Early Cretaceous, Albian, of south central Oklahoma. They are OMNH 700, a dorsal centrum from the Caddo Formation of Marshall County and OMNH 10386, a possible dorsal centrum from the Duck Creek Limestone member of the Caddo Formation of Love County, Oklahoma. This report provides a preliminary examination of the largest and most complete elasmosaur found to date in the State of Oklahoma.