With 100 percent the county's 636 precincts reporting, Becker, who defeated Scaturro during the 2010 primary, won 55 percent to 45 percent.
Both Becker and Scaturro also tried securing the Conservative line. Becker had the party's endorsement, but Scaturro launched a write-in campaign.
Neither Becker nor Scaturro returned calls Tuesday night seeking comment.
Becker, who lost to McCarthy in 2010, had said his experience as a Nassau County legislator and small-business owner made him the key candidate to challenge McCarthy.
"We need to change the way Washington does business," Becker said in a June interview with Newsday. "To do so we need to change the people we send to Washington."
Scaturro argued that Becker "had a chance two years ago and blew it. I'm the only one who can beat McCarthy."
The district -- whose boundaries were redrawn after the 2010 census -- includes the communities of Long Beach, Merrick, Wantagh, Garden City, Mineola, East Meadow, Uniondale, Freeport and Roosevelt. There are 188,933 registered Democrats in the district, 167,815 Republicans and 95,000 voters with no party affiliation.
In the 5th Congressional District -- which covers Southeast Queens, the Rockaways and the Nassau communities of Elmont, North Valley Stream and Inwood -- incumbent Rep. Gregory Meeks defeated three candidates for the Democratic nomination.
The district, remapped as part of the decennial redistricting process, now mirrors Meeks' former 6th Congressional District.
Meeks was challenged by hip-hop artist Michael Scala, former New York City Councilman Allan Jennings and community activist Joseph Marthone. The district includes some 50,000 voters in the Nassau portion.
Republican Randy Altschuler will move ahead with his bid to challenge Democratic incumbent Tim Bishop for Suffolk's 1st Congressional District. Challenger George Demos dropped out of the race in May, but his name still appeared on the ballot. Altschuler received a commanding 87 percent of the vote.