Elisa Mercedes Ruiz Díaz Bareiro (16 October 1964 – 19 May 2021)[1] was a Paraguayan lawyer and diplomat.

[2] In the government, Ruiz Díaz served as Minister of the Permanent Mission of Paraguay to the Organization of American States (OAS), Advisory Minister of Communication of the Presidency of the Republic, General Director of the Post Office, and Chief of Cabinet of the Vice-Presidency of the Republic.

[8] The OAS member countries hold this position in rotation, and Paraguay's previous turn was in 2013.

[9] As chair, Ruiz Díaz pressed for equitable distribution of COVID-19 vaccines among the countries of the Americas.

[10] Ruiz Díaz died on 19 May 2021 in Washington, D.C.[11] The Inter-American Commission on Human Rights said that she had been ill for a year prior.