"If anybody wants to see what's going to happen, they can come to the central committee meeting," he said.
Hansen's term would normally run through June, when state party delegates meet to pick a new party chairman.
Salt Lake County Republican Party Chairman Thomas Wright has declared his candidacy for the state post, but he said Thursday night that he hadn't heard about Hansen's plans.
Hansen ran Hatch's 2004 re-election campaign and is the former political director for the National Republican Senatorial Committee.
But his close relationship with the senator drew scrutiny earlier this year, when The Tribune reported that Hansen had been receiving $5,000 a month from Hatch's campaign, even though he had said he would stop being paid by the senator when Hatch was elected state party chairman a year earlier.
Hansen called the money a bonus for previous work, but other Republicans called the payments inappropriate.
Kirk Jowers, director of the University of Utah's Hinckley Institute of Politics, said Hansen's departure shouldn't come as a surprise.
"Everyone expected Dave, at some point, to step down and take on Sen. Hatch's election [campaign]," Jowers said. "He's been Senator Hatch's closest adviser for years, so its no surprise to anyone that, in a potentially very difficult race, he would not desert his longtime client and candidate."