Nikolai Sergeyevich Leonov (22 August 1928 – 27 April 2022) was a Russian politician, top KGB officer, and the Soviet Union Latin America expert.

At the age of 25, Leonov was assigned to Mexico City, where he studied Spanish at the Autonomous University of Mexico. During the cruise, he met Ral Castro, who was returning from a youth festival in Europe. When he arrived in Mexico, he took a minor position in the Soviet embassy.

Nikolai Sergeyevich Leonov
Nikolai Leonov Children

Leonov met Che Guevara in Mexico City in 1955 through Ral Castro. Leonov broke diplomatic norms by paying a visit to Guevara, who was captivated by Soviet life.

Leonov provided Guevara with Soviet literature after addressing some of his inquiries. When Guevara went to the embassy to pick up the books, the two men spoke again, as they had the last time they spoke in Mexico.

Recalled to Moscow in November 1956, Leonov was released from the foreign service and began to work as a translator for the official Soviet Spanish-language publishing company, Editorial Progreso, planning to pursue a career as a historian of Latin America. He was recruited to join the KGB in the late summer of 1958.

He was married and had children at the time of his death, but little information on his family, including his wife and children, is available.