The Netherlands international had a contract which was due to expire in June 2013 but this latest deal has seen the 23-year-old tied to the Amsterdam-based club for a further three years.
The left-back, who is the son of former Ajax icon Danny Blind, grew up in the Eredivisie giant's youth squad and is believed to be valued at around €2 million.
Ajax director of football Marc Overmars told the club's official website: "We have an agreement and everyone is very satisfied. Daley will play the next three years with Ajax.
"All doubts disappeared. Daley is a full international and at Ajax we hope this will continue."
He made his debut for the Amsterdam club in December 2008 and has gone on to win two Eredivisie titles with the club as well as three caps for his country.
The defender has been a regular this season for the Dutch side, playing 31 times this season.