Isidoro Benítez Casco was a Paraguayan footballer who played as a midfielder.
Benítez Casco represented Paraguay at the 1921 South American Championship, where Paraguay finished fourth and last. He played in all three of Paraguay's matches, against Uruguay, Brazil and Argentina.
A year later, he took part in the 1922 South American Championship, where Paraguay finished as runners-up. Benítez Casco appeared in all five of the team's matches, against Brazil, Chile, Uruguay and Argentina, as well as in the championship play-off against Brazil.
He also played in the 1924 South American Championship, where Paraguay finished third. He appeared in all three matches, against Argentina, Uruguay and Chile.
References Tomasz Wołek, Encyklopedia piłkarska FUJI. Copa America, Wydawnictwo GiA, Katowice, 1995, , pp. 22, 24–25, 37.