Alex Waller and Mike Haywood have extended their deals at Saints.
The pair have become key figures in the front row since emerging from the club's Academy system.
Waller scored the extra-time try that won Saints their first Aviva Premiership title as they beat Saracens in dramatic fashion at Twickenham in May 2014.
Haywood started that match, and the previous week's Challenge Cup final, and has continued to compete with club captain for the No.2 shirt Dylan Hartley ever since.
Haywood was Saints' top scorer last season, registering eight tries, and he again leads the way this time round, having already grabbed five.
The 26-year-old has made 177 appearances in the green, black and gold so far, while loosehead prop Waller has racked up an incredible 227 by the age of 27.
And they will now look forward to plenty more after extending their deals beyond next summer.
“It’s been great to have seen the two of them develop into the players they are today," said Saints boss Jim Mallinder.
“Both of them have played a large part in the club’s history so far and no doubt they are to be a big part of the club’s future.
“We’re delighted they’ve chosen to stay at Saints.”