London Irish quartet Shane Geraghty, Halani Aulika, Darren Allinson and Tom Fowlie have all signed new deals with the club.
Geraghty has signed a three-year extension to his contract with the club which he rejoined in 2012 from Northampton.
The former England international fly-half joined the London Irish Academy in July 2004 and went on to make 71 first team appearances, scoring 197 points before signing for Saints.
Tonga international prop Aulika has also extended his contract by three years, keeping him at the club until the end of the 2016-17. Aulika was the Exiles players' player of the season last term.
Welsh scrum-half Allinson - who joined from Cardiff Blues - has also prolonged his association with the club for three more years.
Winger Fowlie, 18, has made the breakthrough this season, playing in the LV=Cup and Amlin Challenge Cup. He has signed a two-year extension.
The four players follow George Skivington, Ian Humphreys, David Paice, Jon Fisher and Topsy Ojo in committing themselves to the Madejski.
Director of rugby Brian Smith told the club's website: "It's a great way to start the New Year and extremely positive news for the club and our supporters. I'm delighted that all four of them have committed their futures.
"It has been an exciting period for the club off the field and the players are excited by where we want to go on the field.
"Tom Fowlie is going to be a huge part of this club going forward and it is great to see Academy talent coming through the club and going on to represent the first team."