Mitt Romney is expected to win the Utah nomination in a landslide, as he did in 2008. Utah is the last state in the union to hold a 2012 presidential primary.
Orrin Hatch barely avoided the primary during the Utah GOP convention in April, and will face challenger Dan Liljenquist for the opportunity to run against Democratic nominee Scott Howell in November.
Recent polls show Hatch was ahead of Liljenquist, but that didn't stop the challenger's supporters from making a final push to get voters out.
Ryan Combe will face Donna McAleer for the opportunity to run against incumbent Rob Bishop in Utah's 1st Congressional District.
Statewide, the race for the GOP nomination for Utah's next attorney general will also be decided as John Swallow and Sean Reyes vie to replace outgoing AG Mark Shurtleff.
In Salt Lake County, two GOP challengers hope to be their party's nominee for county mayor.
Mike Winder is hoping to beat Mark Crockett for the GOP nomination. The winner will face Democrat Ben McAdams in November.
Stay tuned to ABC 4 News and ABC4.com for all of Utah's primary results.