The Whites found themselves 1-0 down after just two minutes and there was no way back as the Dutch champions eased to victory through strikes from Davy Klaassen, Perr Schuurs, Ryan Gravenberch and Danilo.
Leeds now have one more friendly which comes against Europa League champions Villarreal on Saturday evening, one week before the Premier League opener against arch rivals Manchester United at Old Trafford.
Leeds United writer Lee Sobot hands out the ratings from United's defeat in Amsterdam.
1. Illan Meslier
5 - Not given much help by his side's defending but equally his distribution could have been better and conceding four is not nice for any 'keeper, especially one as good as him. Picture by Getty.
2. Jamie Shackleton
6 - The Whites Academy graduate has had a fine pre-season and was again one of the better players at right back but his night ended short after a heavy whack to the head with 11 minutes left. Looked very shaky when getting up. Photo by Getty.
3. Luke Ayling
5 - United's captain in the absence of Liam Cooper got off to an awful start when losing the ball on the edge of the box which led to the Ajax opener. Started at centre-back and ended up at right back as part of a hard night. Photo by Getty.
4. Pascal Struijk
6 - Probably United's best defensive player who used his physique to stand up to a very good Ajax side. Also a threat at the other end and put a headed chance wide.
Still inexperienced really and still progressing. Photo by Getty Images.