Eduardo Lastenes Colombres Mármol (February 10, 1878 – 1943) was an Argentine diplomat and marine.

He achieved temporary popularity through comments in the press of South American nations on the occasion of his book on the Guayaquil Conference, inspired by a series of documents whose apocryphal nature was widely demonstrated.

[citation needed] He graduated as a midshipman from the Naval Military School in 1900, retiring from the navy in 1906, with the rank of Alférez (currently equivalent to corvette lieutenant).

From 1911 to 1913 he served as Consul General in Calcutta, and as such he represented Argentina at the coronation of George V of the United Kingdom as Emperor of India.

Later, from 1935 to 1936 he held the position of Envoy Extraordinary and Minister Plenipotentiary in Poland and Czechoslovakia, with residence in Prague.