In a letter to Max posted on his Facebook page, Mr Zuckerberg and his wife said they were going to give away 99% of their company shares, with an estimated value of $45 billion.
He said they are donating their fortune because they want to make the world a better place for Max to grow up in.
“Max, we love you and feel a great responsibility to leave the world a better place for you and all children.
“We wish you a life filled with the same love, hope and joy you give us. We can’t wait to see what you bring to this world,” the letter said.