Michael Townsend, Sam Clucas and Dan Hanford have all signed deals that will keep them at Edgar Street until the end of the 2012/13 season.
Centre-back Michael Townsend signed for the Bulls in July 2010 and has gone on to make more than 70 appearances for United in all competitions.
Clucas was recently signed on a short-term deal from the Glenn Hoddle Academy. The former Lincoln youngster has made one start for the Bulls and five substitute appearances, impressing with solid displays on the left of midfield and at left-back.
Goalkeeper Hanford arrived at Edgar Street shortly before Christmas as back-up to David Cornell and Adam Bartlett.
While Dan is yet to feature for the Bulls' first team, he has made a number of appearances in reserve outings, impressing the United management team.
The trio will join the following players in being contracted to the club for next season: Adam Bartlett, Stefan Stam, Joe Heath, Benoit Dalibard, Will Evans, James McQuilkin, Harry Pell.