I don't know,I guess they were always there ever since God created Saturn,but good question +3!

They are believed to be from moons or asteroids that collided with each other, creating a massive ring of debris that orbits around the planet.

Astronomers believe that one of Saturn's satellites got too close to the planet and was torn apart by Saturn's gravity.

No one is sure how Saturn's rings formed, but the picture of how they formed and what they are made of is changing. Saturn's ring system is enormous: from the inner to outer edges, it would reach farther than the distance between Earth and the Moon. The image above was created by NASA based on mapping of the rings in 2005. Images from the Hubble Space Telescope led scientists to believe the rings were relatively youthful and likely created by a comet that shattered a large moon, perhaps 100 million years ago. But recent observations by NASA's Cassini spacecraft, which arrived at Saturn in 2004, show the rings may have been created roughly 4.5 billion years ago when the solar system was still under construction. Features captured by Cassini also show the rings were not formed by a single event, but that the ring material is constantly being recycled and includes material from moons that are continually being shattered, according to researchers at the University of Colorado at Boulder. The findings were presented this week at a scientific meeting in San Francisco. Scientists had thought rings as old as Saturn would be darkened or polluted by meteoric dust, leaving telltale spectral signatures. But the Cassini observations indicate the churning mass of ice and rock within Saturn's gigantic ring system is likely much larger than previously estimated, which explains why the rings appear relatively bright. If the meteor "pollution" is being shared by a much larger volume of ring material, it becomes diluted and appears brighter and more pristine than expected. By observing the flickering of starlight that passes through the rings, researchers have discovered objects in at least one of the rings ranging from 30 yards to six miles across. Since most of the objects were translucent -- indicating at least some starlight passing through them -- the researchers say there are probably clumps of icy boulders that are continually collecting and disbanding as they shatter and come together. Rings: http://weblogs.baltimoresun.com/news/sciencematters/blog/2007/12/post_2.html