Rob Andrews was elected to the U.S. House in 1990 with 56 percent of the vote, defeating Republican Daniel Mangini. He was re-elected in 1992 with 70 percent of the vote, defeating Republican Lee Solomon.
He was re-elected in 1994 with 72 percent of the vote, defeating Republican James Hogan. In 1996, he was re-elected with 76 percent of the vote against Republican Mel Suplee. Andrews won re-election in 1998, defeating Republican Ronald Richards with 73 percent of the vote. He was re-elected in 2000 with 76 percent of the vote.
In 2002, he was re-elected with 93 percent of the vote.
He was elected to freeholder board in 1986 and was re-elected in 1989.
Andrews ran unsuccessfully for the Democratic nomination for governor in 1997, losing to state Sen. James McGreevey.