Saracens-bound Chris Ashton took only five minutes to mark his final home appearance with a try before retiring hurt 14 minutes later.
England full-back Ben Foden, winger Paul Diggin and replacement forwards Teimana Harrison and Alex Waller scored Northampton's other tries with fly-half Stephen Myler kicking 10 points and his replacement Ryan Lamb booting seven.
Worcester replied with a tries from left-wing Josh Drauniniu and number eight Kai Horstmann, both converted by fly-half Danny Gray.
The victory clinched fourth place in the Premiership table for Saints as they joined Harlequins, Leicester and Saracens in the play-offs.
The home side, refusing to take a safety approach, showed their ambition by passing up the chance of a kickable shot at goal after their powerful scrum forced the backpedalling Warriors pack to concede a penalty.
They won the resulting lineout and displayed slick handling to move the ball left to right across the pitch and all the way back before striking.
Flanker James Craig's pass found Foden who turned the ball back inside for the supporting Ashton to score, displaying his trademark swallow dive for the final time in a Northampton shirt at Franklin's Gardens.
The lead lasted only two minutes before Worcester struck back. Full-back Tom Arscott's scything run took him through the Northampton defence and he supplied the final pass to send wing flyer Drauniniu racing in.
Tom May, who replaced the injured Ashton, was forced into touch as he tried to squeeze over in the right-hand corner.
The Warriors, who had defended stoutly, were temporarily reduced to 14 men when skipper Shaun Perry was yellow-carded three minutes from half-time for hands in the ruck in front of his own posts.
The departure of the former England scrum-half turned the game Northampton's way and they took full advantage.
Myler kicked the resulting penalty and Saints made their extra-man advantage pay in first-half injury time when Foden jinked in for their second try as the Worcester defence was stretched beyond breaking point.
Myler converted and the fly-half stretched the lead to 20-7 with his second penalty when the Worcester scrum transgressed once more five minutes into the second half.
Worcester conceded 13 points while Perry was binned and the captain did not re-appear when his 10 minutes was up as the Warriors sent on Johnny Arr as his replacement.
The swap paid off almost immediately as a Worcester ruck forced Northampton back over their own line and Horstmann, who is moving to Exeter, got the finishing touch for a try converted by Gray.
Northampton responded with a 53rd-minute penalty from Lamb, two minutes after he replaced Myler.
Lamb was also on target with a touchline conversion after Diggin sprinted in for Northampton's third try after 58 minutes.
New Zealander Harrison secured the bonus point with their fourth try - and his first for the club - in the same corner eight minutes later but this time Lamb's kick was just short.
Passing up another easy penalty shot, Saints won again won the resulting lineout before driving in replacement prop Waller for their fifth try, with Lamb adding the extras.
Two minutes from time, replacement hooker Ed Shervington became the second Worcester player to be sin-binned.
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