Castillo enjoyed a legendary professional career, finishing with an extremely impressive record of 67 wins, 10 losses, and two draws.
He began a remarkable 43-0, before finally losing to Alexis Arguello while fighting for the WBC super featherweight title in 1980.
The Texan fought several boxing legends during his career, including the likes of Julio Cesar Chavez, Salvador Sanchez, and Juan Laporte.
Plenty of fans have paid tribute to Castillo.
After retiring, Castillo began working as a broadcaster.
He called fights for ASPN before the channel’s rebranding.
Castillo had six children with wife, Cindy.
Upon hearing of Castillo’s death, WBC president Mauricio Sulamain wrote on Instagram: “It is with deep sadness that I have learned of the passing of my dear friend and champion Ruben Castillo.
“Now he is in the arms of God.
“May his wife, Cindy, family, and friends find comfort with the support of so many who loved Ruben. Rest in eternal peace.”
