The Hurricanes announced the deals three days before the players could have become unrestricted free agents.
Pitkanen agreed to a three-year contract that will pay him $4.5 million per season, the Hurricanes said. Dwyer received a two-year deal and will make $600,000 this season and $650,000 in 2012-13.
Pitkanen, 27, led Carolina defensemen last season with 30 assists. He made $4.5 million last season and remains the team's highest-paid defenseman. The Hurricanes earned points in the standings in 26 of the 30 games in which he had either a goal or an assist.
"Joni has been a very important part of our defense as he plays in all situations," general manager Jim Rutherford said. "He plays a lot of minutes, and is one of the top puck movers in the league. We are very pleased that he wanted to return to the Hurricanes."
Dwyer, 28, made $500,000 last season and had career highs of eight goals, 10 assists and 80 games played.
"Patrick has become a durable and reliable NHL forward," Rutherford said. "He is a very strong penalty killer, and he brings a lot of speed and energy to our group of forwards."