Robles captured 74 percent of the delegate vote at Saturday's Salt Lake County Democratic Convention to secure the party's nomination. The District 1 area includes the neighborhoods of Rose Park, Glendale and Poplar Grove and is a Democratic stronghold.
"I'm looking forward to bringing more energy to the district," Robles told a room of screaming delegates after her win was announced.
Fife thanked people from his district for letting him serve them, and told Robles the fight against Republican nominee, Salt Lake City Councilman Carlton Christensen, could be tough.
"You'll have to work hard to beat your Republican opponent," he said. "But I'm here to help you."
Fife has served just one term in the Senate. Prior to that he served several years in the Utah House.
Robles is former director of the state's Ethnic Affairs Office. She has been knocking on doors in a grass-roots campaign for months.
She already has a meeting planned for Monday to begin to register voters in her district.
"It's been great to see the response," she said. "Truly, people are just hungry for change."
The Senate race was the only one in Salt Lake County with a Democratic incumbent challenged within the party.
However, six other races were contested.
In Magna's District 22, Sue Duckworth won the nomination with more than 60 percent of the vote, so she will run to replace her husband, incumbent Rep. Carl Duckworth, who is battling a rare form of bone marrow cancer.
"There's a lot of love in this room," Sue Duckworth said as delegates and family members congratulated her. She faces Constitutional Party candidate Thomas Mangum, but no Republican challenger as Deena Ely dropped out of the race earlier this week.
Delegates also elected a new county party chairman. As expected, Weston Clark was picked to replace Christian Burridge, who resigned a few days ago.
