Newcastle would not disclose the fee. The 23-year-old Holland international has signed a five-year deal at St James' Park.
Alan Pardew: "We are delighted to secure the services of Vurnon.
"He is an exceptionally talented footballer with great technical ability, which is exactly what I'm looking at in a player.
"And, at 23 years old, we hope his best years are at Newcastle.
"He has come through the Ajax youth system which is world renowned for bringing up players the right way, and I am sure he will fit seamlessly into the squad of players we have here.
"Vurnon has done his pre-season, and indeed already played one competitive game, so he's up to speed and ready to play when I need him."CARDIFF CITY 4 NEWCASTLE UNITED 1
Alan Pardew said (before the visit to Wales) that the pre-season fixtures had "gone according to plan".
But it all went sadly wrong in the last game before the visit of Tottenham next week . to give the Toon boss a right kick in the balls at a time when he least expected it.
The Magpies were beaten 4-1, and they found themselves 3-0 down at half-time on a day his team were SHOCKING.
Demba Ba and Papiss Cisse were rested, and Hatem Ben Arfa and Yohan Cabaye were left back on Tyneside to work on fitness, so at least we have the cavalry to arrive next week.
But this was not what the boss had hoped for, and will obviously be a reality check before the season starts in six days.
The first chance fell for the home side on seven minutes Aron Gunnarsson saw Ryan Taylor sweep the ball clear off the line.
Newcastle’s first real glimpse of goal came on nine minutes when Gutiérrez tried a shot, but goalkeeper David Marshall claimed easily.
But on 16 minutes Cardiff were ahead when Peter Whittingham picked out Gunnarsson on the right hand side before his volley left Tim Krul with no chance.
Four minutes later and the Magpies found themselves 2-0 down when Jordan Mutch picked out Joe Ralls before he kept his composure to guide it calmly past Krul.
After 26 minutes United conceded a third goal after being caught on the break.
They failed to clear their lines and Gunnarsson applied the finish from close range.
Pardew replaced Ryan Taylor with James Perch to shore up the out-played midfield.
With 48 minutes on the clock sub Haris Vuckic put in a teasing ball for Gutiérrez but the Argentine was fouled with ref Mark Whitby pointing to the spot.
Shola Ameobi stepped up and calmly placed it to the right hand side of Marshall to reduce arrears.
But Cardiff still looked a solid unit and Krul denied them a fourth when he tipped Filip Kiss’ effort over the top.
Chances for Gutiérrez and Davide Santon went just wide as Newcastle looked to get back into the game.
However, sub Etien Velikonja bundled his way through the Toon defence chasing a long ball, and rammed it past Krul with 14 minutes left.
United boss Pardew handed a debut to Adam Campbell with seven minutes left.
The young Geordie played in Romain Amalfitano within moments of coming on and the Frenchman was unlucky to see his shot saved by sub keeper Joe Lewis.
CARDIFF: Marshall (Lewis 80), McNaughton (Blake 73), A Taylor, Hudson, Turner, Whittingham, Conway, Gunnarsson, Mutch, Ralls (Earnshaw 71), Helguson (Velikonja 39).
UNITED: Krul, Simpson, Coloccini (Williamson 46), Steven Taylor (Gosling 63), Santon, Obertan (Campbell 83), Tiote (Amalfitano 71) , Gutiérrez, Marveaux (Vuckic 46), R Taylor (Perch 28), Shola Ameobi.PRE-SEASON FIXTURES:
CARDIFF CITY 4 NEWCASTLE 1 (Shola Ameobi pen)Krul, Simpson, Coloccini (Williamson 46), Steven Taylor (Gosling 63), Santon, Obertan (Campbell 83), Tiote (Amalfitano 71) , Gutiérrez, Marveaux (Vuckic 46), R Taylor (Perch 28), Shola Ameobi.
HARTLEPOOL 1 NEWCASTLE 5 (Shola Ameobi, Marveaux 2, Obertan, Vuckic)Harper (Alnwick 82), Simpson (Good 72), Tavernier, Williamson, S.Taylor (Vuckic 46), Perch (R.Taylor 72), Gosling, Amalfitano (Santon 80), Marveaux (Obertan 78), Sh.Ameobi (Ben Arfa 46), Bigirimana (Abeid 59).
DEN HAAG 0 NEWCASTLE 0Krul; S Taylor (Gosling 65), R Taylor (Perch 71), Coloccini, Santon (Simpson 80); Obertan (Bigirimana 71), Tiote (Ameobi 71), Vuckic (Williamson 65), Gutierrez; Ba (Amalfitano 82), Cisse
BRAGA 1 NEWCASTLE 2 (Ba, R Taylor)Harper; Simpson, Tavernier, Coloccini, R.Taylor; Sammy Ameobi (Obertan 88), Tiote (Cabaye 70), Gutierrez, Marveaux; Cisse, Ba (Vuckic 85).
OLYMPIACOS 1 NEWCASTLE 1 (S Taylor)Krul, Perch, Williamson, S.Taylor (Dummett 46), Santon, Obertan (Sammy Ameobi 72), Bigirimana, Gosling (Abeid 36), Amalfitano, Vuckic, Shola Ameobi (Cisse 72).
FENERBAHCE 1 NEWCASTLE 1 (Abeid)Elliot, Simpson (Santon 68), Tavernier, Coloccini, R Taylor, Tiote (Bigirimana 59), Gosling (Abeid 73), Obertan (Shola Ameobi 75), Marveuax (Gutierrez 59), Vuckic (Sammy Ameobi 46), Ba (Cisse 68).
MONACO 0 NEWCASTLE 1 (Ba)Harper, Santon (Ryan Taylor 57), Simpson, Williamson (Perch 46), Gutierrez, Amalfitano (Obertan 62), Abeid (Tavernier 46), Bigirimana (Tiote 62), Sammy Ameobi (Vuckic 46), Shola Ameobi (Gosling 62), Ba (Marveaux 78)
CHEMNITZER 1 NEWCASTLE 0Elliot; Tavernier (Simpson, 70), Williamson, Perch, R Taylor (Santon, 70); Obertan (Gutierrez, 77), Abeid (Bigirimana, 70), Gosling, Amalfitano; Vuckic (Shola Ameobi, 70), Sammy Ameobi (Ba, 77). Sub not used: Harper. Att: 6,700