Borowiecki had three points in a career-high 70 games last season and led the NHL in hits (364) and penalty minutes (154).
The 28-year-old Ottawa native was limited to two playoff games after suffering an injury in the Senators’ first-round series against Boston.
His contract extension will carry an average annual value of $1.2 million in the 2018-19 and 2019-20 seasons, the Senators said in a release.
Borowiecki was selected by Ottawa in the fifth round (139th overall) of the 2008 NHL Draft.
He has four goals, 13 assists and 436 penalty minutes in 217 career NHL games.