In August, at the Russian Cup, she won gold on beam (15.375) and bronze on vault (13.463), and placed eighth all-around and fourth on floor. In October, Dementyeva was the youngest gymnast competing at the 2010 World Gymnastics Championships. Here, she made a significant contribution to Russia's team gold medal-winning performance by competing on uneven bars (13.366), beam (14.400), and on floor (14.533). She also made the beam final, placing sixth with a score of 13.966. Later that year she had a good showing at the DTB Cup in Stuttgart where she won silver on floor, and bronze on beam and uneven bars. Her final 2010 competition was the Toyota Cup, where she won silver on uneven bars and placed fifth on floor. She also placed seventh on beam after suffering two falls.