Prior to her birth, her uncle, King Alfonso XIII, declared that any children born of her parents' marriage would be Infantes or Infantas of Spain.

[3] She had two elder brothers, Luis Alfonso (1906–1983) and José Eugenio (1909–1966), and one younger sister, María del Pilar (1912–1918).

On 29 August 1946, Infanta María de las Mercedes married Prince Irakli Bagration of Mukhrani at the Miramar Palace in San Sebastián.

[4] On the advice of Grand Duke Vladimir Kirillovich of Russia,Infante Juan, Count of Barcelona, head of the Spanish royal family in exile, recognised the union as dynastic.

[5] They had two children: Princess María de las Mercedes died on 11 September 1953 in Madrid from a pre-existing heart condition.