Dio announced last summer he was battling stomach cancer. According to his website, he had been undergoing treatment at a Houston hospital.
Dio is often credited for popularizing the "devil's horn" hand gesture in metal culture.
His wife Wendy, said on his website, "Today my heart is broken ... Many, many friends and family were able to say their private good-byes before he peacefully passed away. Ronnie knew how much he was loved by all. We so appreciate the love and support that you have all given us. Please give us a few days of privacy to deal with this terrible loss. Please know he loved you all and his music will live on forever."