His daughter Bettsimar Diaz confirmed his death on her Twitter account, but gave no details.
Most often-performed song is "Caballo Viejo," which translates as "Old Horse."
It was one of more than 200 songs he composed while recording 70 albums. His popularity grew as he hosted a children's television show and appeared in five films.
Both the leftist government and its opponents in the bitterly divided nation paid homage to the singer today. Education Minister Hector Rodriguez says a song in honour of Diaz will be performed in all Venezuelan schools tomorrow.