The 9th District includes all or part of 14 counties in Southcentral Pennsylvania.
Shuster, 43, of Hollidaysburg, Pa., won the seat in a special election in 2001 after his father, Bud Shuster, resigned. Bud Shuster had served in Congress since 1972.
DelGrosso, 33, of Tipton, Pa., is a U.S. Naval Academy graduate who left a job with a consulting firm to make his first run for political office.
DelGrosso campaigned as a fiscal conservative who would provide more leadership in the House. Shuster pointed to his votes on issues such as tax cuts, Medicare reform, homeland security and the war against terrorism.
Both men have master's of business administration degrees, Shuster's from American University and DelGrosso's from the University of Michigan.
In the primary campaign, Shuster said his experience would be the deciding factor in the race, while DelGrosso said he wanted to become one of "a handful of congressmen from Pennsylvania that you can count on as fiscal conservatives."
The winner will run against Paul I. Politis in the November general election. Politis is a Greencastle, Pa., resident and vice chairman of the Franklin County Democratic Committee. He was unopposed in the Democratic primary.
The position pays $154,700 annually, according to the U.S. Congress Web site.