The pair are included in a 28-man squad for the World Cup qualifiers against Malta and Slovakia as Gareth Southgate's side look to move towards securing their place at the tournament in Russia.
Chalobah has impressed since joining the Hornets from Chelsea in the summer while Maguire was a standout for Hull City, despite their relegation from the Premier League in 2016-17, and opened his Leicester account against Brighton on Saturday.
Elsewhere, Jordan Pickford is the only uncapped player included in the squad, with the Everton shot-stopper one of four goalkeepers selected by Southgate.
Pickford will battle it out with Joe Hart, Jack Butland and Tom Heaton for the No.1 spot, with Southampton's Fraser Forster omitted.
Jermain Defoe keeps his place despite starting Bournemouth's opening two matches of the season on the bench.
The squad announcement comes just a day after Wayne Rooney declared his retirement from international football in spite of Southgate offering him a route back into the fold.
England squad: Butland, Hart, Heaton, Pickford; Bertrand, Cahill, Cresswell, Jones, Keane, Maguire, Smalling, Stones, Trippier, Walker; Alli, Chalobah, Dier, Henderson, Lingard, Livermore, Oxlade-Chamberlain, Sterling; Defoe, Kane, Rashford, Sturridge, Vardy, Welbeck.