We here report an ankylosaurian ilium from the Albian–Cenomanian Longjing Formation of Yanji City, Jilin Province, northeastern China. The diagnostic features allowing referral of this specimen to Ankylosauria include: an ilium rotated horizontally dorsal to the acetabulum with the primitive lateral surface facing ventrally; long and laterally divergent preacetabular process; and a shallow, cup-like acetabulum. This new specimen represents the first definitive ankylosaurian dinosaur from Jilin Province, and the easternmost ankylosaurian occurrence in China. The present discovery demonstrates the potential for future finds in the Longjing Formation, especially in the Longshan fossil beds of Yanji City, such as additional ankylosaurian or other dinosaur remains that might provide significant data on dinosaur evolution during the middle Cretaceous of eastern Asia.