The 23-year-old attacking midfielder has signed a five-year contract with the option of a further 12 months at the Premier League side.
West Ham will pay Ajax €41.5million (£35.6m) plus €3m (£2.5m) in easily attainable add-ons, with the Eredivisie club retaining a 10 per cent sell-on clause if he ever moves on to another club.
Kudus will wear the No. 14 shirt at West Ham and will hope that he can repeat his dazzling form with Ajax where he bagged 27 goals in 87 appearances across all competitions.
The Ghanaian midfielder said: “I’ve been dreaming to play in a league like this since I was a kid.”
The Premier League is dream of most young players, especially those from Africa and admitted his delight and vowed to continue improving. He added: “I’ve been dreaming of this moment and I’m so happy to be here. But it doesn’t stop here, I want to keep going.
“I try my best to entertain the fans as I think that’s what football all is about. I’m just here to do my best and help the team. I’m really happy to be here. I will fight for the badge. I can’t wait to get started.”
West Ham manager David Moyes who has been crying out for signing welcomed the midfielder after beating competition from Chelsea and Brighton and Hove Albion for his signing. “I’m delighted we’ve been able to bring Mohammed to West Ham United,” Moyes said.
The Scottish manager will hope that the Ghanaian will be ready to make his debut against newly promoted side Luton Town on Friday night.