Rocky Marciano's brother Peter and son Rocky Marciano, Jr., are working with executors of the estate and director/writer Dustin Marcellino on 49-0/The Brockton Blockbuster.
A statement from Marcellino reads: "Rocky Marciano was my great grandfather's all-time favorite fighter, which was passed down to all of us in the Marcellino's family.
"The Marcellinos and the Marcianos have truly become family during the development of this project and we are honored to tell this generation about a man, a son, a brother, a husband and a father who rose up out of the streets of Brockton to change the world in his generation."
Marciano, Jr. adds, "My father is still counted as one of the greatest heavyweight fighters of all time and if he were alive today he would be proud that we are working to bring the true story of his life to the big screen. I am thrilled that the Marciano family; together with City of Peace films is working on a movie that will tell the story about my father... the real Rocky story."
The movie will be filmed in Marciano's hometown of Brockton, Massachusetts.
The boxing great died in a plane crash in August, 1969, on the eve of his 46th birthday.