Saracens have awarded new contracts of undisclosed lengths to Owen Farrell, Mouritz Botha, Ernst Joubert, Duncan Taylor, Sam Stanley and Ben Spencer.
Sarries plan to announce 12 other deal extensions across Thursday and Friday.
Centre Farrell, 20, and lock Botha, 30, have started both of England's opening Six Nations games.
The son of Saracens coach Andy Farrell, he made his first-team debut in October 2008 and has gone on to play 46 times for the reigning Premiership champions, amassing 603 points, 213 of which have come this season.
Saracens director of rugby Mark McCall said: "Owen obviously has a wonderfully exciting future in the game, at club and international level, and we are delighted he has pledged his future to Saracens."
Scrum-half Spencer, 19, was thrust into first-team action in November following injuries to Richard Wigglesworth and Neil de Kock.
The former Cambridge man has featured in 20 games this term and made a try-scoring debut for England Saxons in a 23-17 win over Irish Wolfhounds in January.
Botha, who has three England caps to his name, is in his third season with Saracens, where he has made 77 appearances.
South African number eight Joubert arrived at the north London club from Johannesburg outfit Lions in 2009.
The 31-year-old has scored 157 points across his 81 games for McCall's side.
Centre Taylor, 22, a summer signing from Bedford Blues, has featured eight times this season, while 20-year-old fly-half Stanley has been limited to four senior appearances.