Mirta Francisca de la Caridad Díaz-Balart Gutiérrez

Mirta was Fidel Castro's first wife. She was the daughter of América Gutiérrez and Rafael José Díaz-Balart, a prominent Cuban politician before 1959 (Minister of Communications, mayor of the city of Banes).

Mirta was studying Philosophy at the University of Havana when she met and married law student Fidel Castro.

Castro and Díaz-Balart married on October 11, 1948. They spent a honeymoon month in New York and Miami. They divorced seven years later, in 1955, while Castro was in exile, due to Castro's infidelity and his violent activities. Soon after, Mirta Díaz-Balart and Castro had a son, Fidelito, born in 1949. After the divorce, Castro lost custody of his son and became estranged from him.

In 1956, Mirta Díaz-Balart married Emilio Núñez Blanco, son of a former Cuban ambassador to the UN, Emilio Núñez Portuondo. The couple lived with their children in Havana.

With the victory of the Cuban guerrilla, Mirta Díaz-Balart moved with her family to live in Madrid. Her son remained in Cuba for many years, studying in Cuba and later in the Soviet Union.

The Miami Herald stated in 2000 that she was still living in Spain, and that occasional visits to Cuba were organized by Raúl Castro himself. In 2018, the year of Fidel's son's death, Mirta Díaz-Balart was still living in Cuba, at the age of 90. She passed away in Madrid, Spain in 2024.

Mirta Díaz-Balart is the aunt of anti-Castro Republican Party politician Mario Díaz-Balart, his brother Lincoln Díaz-Balart, and television journalist José Díaz-Balart.