Both clubs sit in mid-table after promising starts to the new season, despite major outgoings for the two over the summer.
Match preview
There is plenty of pressure on Julen Lopetegui to succeed following the achievements of David Moyes in charge of the Hammers, and after three excellent cup journeys in Europe, a domestic cup run will be high on the agenda.
After an opening day defeat to Aston Villa at home, West Ham responded with a fine 2-0 win over fellow London side Crystal Palace at Selhurst Park at the weekend.
Tomas Soucek and Jarrod Bowen scored the two second half goals to hand Lopetegui his first win in charge, and the Spaniard will hope they quickly make that back-to-back victories in this cup clash.
After competing in Europe for the past three seasons, West Ham will now play in the second round for the first time in four years in a competition they have a decent recent record in.
Despite being thrashed 5-1 by eventual winners Liverpool in the quarter-finals last season, that was the sixth time they have gone that far since 2011, as two of those runs also saw them reach the semis.
Falling just short has been common though, as the Hammers have never won the competition, and not reached the final since 1981, so after the Conference League success in 2023, supporters will be thirsty for more success.
Bournemouth will come into this tie still incensed from the late drama in their 1-1 draw with Newcastle United on Sunday.
Dango Ouattara's injury-time header looked like it had won the game for the Cherries, but a dubious VAR call saw the goal chalked off for handball, a decision which left manager Andoni Iraola absolutely furious on the touchline, and one his coaching staff sent off.
After a superb first-half performance which saw Bournemouth lead, they did ride their luck slightly as a Newcastle onslaught saw them level up the score, but unable to add a second.
Nobody could have begrudged Bournemouth the win though, but it is two 1-1 draws from two for the Cherries, who are still adjusting to life after Dominic Solanke.
With an Everton side in disarray next up on their Premier League calendar, a positive result here in the capital could set them up perfectly for that trip to Goodison Park.
Bournemouth have only lost once at this stage since becoming a Premier League club, and their eventual eliminations have been unfortunate.
The club have exited the EFL Cup at the fourth round in both of the last two seasons - to eventual champions Liverpool last season, and finalists Newcastle the season before.
West Ham United form (all competitions):
Bournemouth form (all competitions):
Team News
After a summer of heavy spending, the West Ham faithful may get the chance to see many of their new faces from the start here.
Niclas Fullkrug is the obvious contender to come in up front, while Crysencio Summerville could also start just behind the German, as Bowen and Lucas Paqueta may be rested.
In defence, Aaron Wan-Bissaka and Jean-Clair Todibo are both set for debuts even though the West Ham rearguard successfully shut Crystal Palace out at the weekend.
Iraola handed a debut to new record signing Evanilson at the weekend, as Solanke's replacement looked lively and was unfortunate not a notch a first Bournemouth goal.
With plenty of options on the bench, Iraola may be tempted to rotate here, as Ouattara, Alex Scott and Luis Sinisterra all may come into the side, along with new boy Dean Huijsen at the back.
On the injury front, Enes Unal remains out up top, while Tyler Adams and David Brooks are also still sidelined.
West Ham United possible starting lineup:
Fabianski; Wan-Bissaka, Kilman, Todibo, Emerson; Alvarez, Ward-Prowse, Soucek; Summerville, Fullkrug, Kudus
Bournemouth possible starting lineup:
Neto; Smith, Zabarnyi, Huijsen, Kerkez; Cook, Christie, Scott; Sinisterra, Evanilson, Ouattara
We say: West Ham United 2-1 Bournemouth
After Moyes's cup exploits, an exit this early from a cup competition would not go down too well, despite the strong opponents in front of West Ham here.