The moon was spotted by the international Cassini spacecraft. It measures about a third of a mile wide.
The discovery was announced Tuesday in a notice by the International Astronomical Union.
Researchers have long puzzled over the formation of Saturn's G ring, one of the planet's more mysterious arcs. They now think the G ring was likely formed from icy debris that scattered when meteorites crash into the newfound moon.
Scientists confirmed the moon's existence last summer after analyzing images from Cassini. Saturn has over five dozen moons.