Isaac Francisco Rojas Madariaga (December 3, 1906 – April 13, 1993) was an Argentine Admiral of the Navy and de facto Vice President of Argentina.

Credited with leading the Navy during the rebellion, Rojas obtained Perón's resignation and exile by commandeering the ARA General Belgrano - threatening to bombard the YPF refinery in Ensenada (then the nation's largest).

Rojas imposed a staunch anti-Peronist and anti-Communist as vice president, though he supported Aramburu's call for Constitutional Assembly elections in 1957, overcoming objections from the largely conservative Navy.

[2] Following the return to democracy with the election of President Arturo Frondizi, Rojas remained a vocal supporter of military action to prevent the return of Peronism, and participated in the failed April 1963 coup attempt against President José María Guido (who was himself appointed in Frondizi's replacement for the sake of preventing a Peronist resurgence at the polls).

Following Army Chief Juan Carlos Onganía's defeat of the coup attempt, Rojas was confined to his uptown Buenos Aires apartment, after which he largely limited his contact with the public to occasional columns in conservative newspapers such as La Prensa and La Nación.