The 25-year-old, who will sign a contract until 2013, will not be available for Real until January when he will be available to replace compatriot Ruud van Nistelrooy, who has been ruled out for the rest of the season with a knee injury.
In a separate statement, Ajax said Real would pay up to 27 million euros ($34.4 million), made up of a 20 million euro fixed payment and a 7 million euro variable payment.
Huntelaar's first appearance for the side will depend on how quickly he recovers from an ankle injury that has sidelined him since the beginning of last month.
"I grant Klaas Jan this transfer, though we preferred to finish this season with him," Ajax coach Marco van Basten was quoted as saying in a statement.
The news will come as a much needed lift for an injury-ravaged Real Madrid who have put in a string of unimpressive performances recently.
They were dumped out of the King's Cup by third tier Real Union, lost home and away to Juventus in the Champions League, and in the league suffered morale-sapping defeats against modest Real Valladolid and Getafe.
They have slipped down to fourth in the standings, six points behind leaders Barcelona and have up to eight first team players out injured.
PURE NUMBER NINE
Huntelaar will be competing with Raul and Gonzalo Higuain for a place in the starting line up.
Javier Saviola does not appear to have the confidence of coach Bernd Schuster and rarely features.
Crucially for Schuster, Ajax did not qualify for the Champions League this year so Huntelaar will be eligible to represent Real Madrid in the competition when the first knockout round gets underway next February.
The presence of another five Dutch compatriots in the Real squad -- Van Nistelrooy, Arjen Robben, Wesley Sneijder, Rafael van der Vaart and Royston Drenthe -- should help make the new striker feel at home.
Huntelaar, capped 18 times with 10 goals, debuted for Ajax in January 2006 after being signed from Heerenveen, and scored a total of 105 goals in 136 appearances.
