Perreault received a two-year contract worth $2.1 million. Beagle got a three-year deal worth $2.7 million.
The 24-year-old Perreault set career highs with 16 goals and 14 assists last season. He also had his first career NHL hat trick and made his Capitals playoff debut.
Perreault was a sixth-round draft pick by Washington in 2006. He has 27 goals and 26 assists in 120 career NHL games.
The 26-year-old Beagle had four goals in 41 games last season. He also won 57.7 percent of his faceoffs, ranking second on the team.
Beagle was signed by Washington as an undrafted free agent in 2008. He has seven goals and three assists in 82 career NHL games.