Democrat Janice Hahn beat Republican Craig Huey in a special election to succeed U.S. Rep. Jane Harman, who left her congressional seat to run a think tank.
Unofficial returns from Tuesday's election to fill California's 36th Congressional District seat indicated Hahn won 54.6 percent to Huey's 45.4 percent, the Los Angeles Times reported.
Hahn opened with an early lead and held on in the hard-fought and contentious election to keep the seat in the Democrats' hands.
Turnout was just more than 23 percent, but still higher than the May 17 primary, when less than 13.8 percent of voters cast ballots to put Hahn and Huey in the top two places in a 16-candidate field.
Hahn, from a prominent local political family, raised about $1.3 million to about $1.1 million raised by Huey, a marketing firm owner and publisher of Christian voter guides, the Times said.
Hahn's mother died unexpectedly Monday, forcing the candidate to scale back last-minute campaign activities.