Kaka, 30, created the second goal with a cross from the right side for French striker Karim Benzema who finished it superbly with a bicycle kick.
The Seleção midfielder enjoyed an excellent performance at the heart of Real’s play as they ran riot in the Amsterdam Arena.
The first goal of the evening came courtesy of a Ronaldo tap in from a Benzema pull back, and Benzema grabbed the second with a sensational overhead shot.
Ajax reduced the deficit to 2-1 after a Niklas Moisander header but Real reclaimed their two goal lead after Ronaldo cheekily chipped the goalkeeper from the edge of the box after being put through one on one.
Ronaldo then completed his hat trick with a superb curling strike from outside of the box to give Real the three points.
Real Madrid now lead Group D with six points whilst Ajax remain bottom without a point to their name.
Real now face rivals Barcelona in the Clásico on Sunday.
