The Associated Press reported that Cates died in her sleep on Sunday at her home in Texas.
"Darlene was the best acting mom I ever had the privilege of working alongside," DiCaprio wrote Tuesday.
He continued, "Her endearing personality and incredible talent will live on in the memories of those who knew her, and those who loved her work. My thoughts and prayers are with her family during this difficult time."
DiCaprio was just a teen when he filmed "Gilbert Grape," and it was the first of five Oscar nods for the acclaimed actor, who finally took home a win at the 2016 awards for his work in "The Revenant."
The Associated Press contributed to this report.