The 50-man group will meet up at Pennyhill Park on Monday 22 June to begin preparing for the tournament, which starts against Fiji, at Twickenham, on Friday 18 September.
England will also face France home and away and Ireland at Twickenham as part of the QBE Internationals as they build towards the World Cup.
Five eye-catching inclusions are Luke Cowan-Dickie, Maro Itoje, Sam Burgess, Elliot Daly and Henry Slade, all of whom featured in an 18-9 victory for England Saxons over Ireland Wolfhounds back in January.
Calum Clark and Ed Slater bring the tally of uncapped players to seven. Each of them will be vying for a Test debut.
Leicester Tigers lock Slater, who skippered England in a 38-7 defeat of the Crusaders last June, will join the squad following his recent return from a long-term knee injury. Joe Launchbury, David Wilson and Ben Morgan also get the nod following long periods on the sidelines this season.
Elsewhere, wings Chris Ashton and David Strettle are included on the back of exceptional Aviva Premiership campaigns. In Saracens’ surge to a play-off against Northampton Saints, they have scored 20 tries between them.
Looking ahead to an extensive and exacting training schedule with 50 players, England Head Coach Lancaster explained his selection.
He said: “We are excited to name this extended squad, which allows us to look at a wide group of players who have been pushing hard for selection in training with us or playing well for their clubs this season.
“It’s great to be able to include Alex Corbisiero, Joe Launchbury, Ben Morgan, Ed Slater and David Wilson. They all missed the RBS 6 Nations because of injury and are close to returning to play or have recently begun playing again.
“There are a lot of experienced internationals within the squad with the likes of Chris Ashton and David Strettle, who are in great form for Saracens, coming back.
“It’s also good to have young players like Luke Cowan-Dickie, Elliot Daly, Maro Itoje and Henry Slade in there. They have come through our player development pathway and had great seasons for their clubs.
“Ben Foden, Joe Simpson and Tom Croft have not been included at this stage due to ongoing rehabilitation from injury but will hopefully come into consideration nearer the tournament.
“A number of this 50-man squad, such as Joe Launchbury, Elliot Daly, Danny Cipriani and Marland Yarde will be involved in the England XV side playing the Barbarians on 31 May following the Aviva Premiership semi-finals.
“There will also be opportunities for the likes of Dave Ewers and Christian Wade, who just missed out on the initial selection but could come back in further down the line.”
The England squad to play the Barbarians will be announced at 5pm on Sunday once the Aviva Premiership finalists are known as a number of players from the losing semi-finalists could be involved.
Players from Gloucester Rugby would also not be considered should they reach the European Rugby Champions Cup qualification final.
This training squad is set to be reduced prior to the training camp in Denver and subsequently reduced again as the QBE Internationals approach, with the final 31 players for the Rugby World Cup being announced by the 31 August deadline.
England Rugby World Cup training squad (50)
Chris Ashton (Saracens)
Dave Attwood (Bath Rugby)
Brad Barritt (Saracens)
Kieran Brookes (Newcastle Falcons)
Mike Brown (Harlequins)
Luther Burrell (Northampton Saints)
Sam Burgess (Bath Rugby)
Danny Care (Harlequins)
Danny Cipriani (Sale Sharks)
Calum Clark (Northampton Saints)
Dan Cole (Leicester Tigers)
Alex Corbisiero (Northampton Saints)
Luke Cowan-Dickie (Exeter Chiefs)
Elliot Daly (Wasps)
Lee Dickson (Northampton Saints)
Kyle Eastmond (Bath Rugby)
Nick Easter (Harlequins)
Owen Farrell (Saracens)
George Ford (Bath Rugby)
Alex Goode (Saracens)
Dylan Hartley (Northampton Saints)
James Haskell (Wasps)
Maro Itoje (Saracens)
Jonathan Joseph (Bath Rugby)
George Kruis (Saracens)
Matt Kvesic (Gloucester Rugby)
Joe Launchbury (Wasps)
Courtney Lawes (Northampton Saints)
Joe Marler (Harlequins)
Jonny May (Gloucester Rugby)
Stephen Myler (Northampton Saints)
Ben Morgan (Gloucester Rugby)
Matt Mullan (Wasps)
Jack Nowell (Exeter Chiefs)
Geoff Parling (Leicester Tigers)
Chris Robshaw (Harlequins)
Henry Slade (Exeter Chiefs)
Ed Slater (Leicester Tigers)
David Strettle (Saracens)
Billy Twelvetrees (Gloucester Rugby)
Billy Vunipola (Saracens)
Mako Vunipola (Saracens)
Anthony Watson (Bath Rugby)
Rob Webber (Bath Rugby)
Richard Wigglesworth (Saracens)
David Wilson (Bath Rugby)
Tom Wood (Northampton Saints)
Marland Yarde (Harlequins)
Ben Youngs (Leicester Tigers)
Tom Youngs (Leicester Tigers)
31 May – England XV vs Barbarians, Twickenham, kick-off 3pm
15 August – England vs France, QBE International, Twickenham, kick-off 8pm
22 August – France vs England, Stade de France, kick-off 8pm (BST)
5 September – England vs Ireland QBE International, Twickenham, kick-off 2.30pm
18 September – England vs Fiji, RWC 2015, Twickenham, kick-off 8pm
26 September – England vs Wales, RWC 2015, Twickenham, kick-off 8pm
3 October – England vs Australia, RWC 2015, Twickenham , kick-off 8pm
10 October – England vs Uruguay, RWC 2015, Manchester City Stadium, kick-off 8pm
There are still tickets for Rugby World Cup matches available from tickets.rugbyworldcup.com
Courtesy of RFU