Eufrosina Dvoichenko-Markov was an American citizen and spy for the New York KGB Rezidentura from 194 to 1945. Her son Sgt. Demetrius Dvoichenko-Markov of the United States Army, also woked for Soviet intelligence. Eufrosina Dvoichenko-Markov provide Soviet intelligence with information on Romanians and Carpatho-Russians and other exile groups in the United States. Dvoichenko-Markov also provided information on United States Department of State personal with whom she had contact.
Eufrosina Dvoichenko-Markov codename in Soviet intelligence is "Masha ". Dvoichenko-Markov is referenced in the following Venona project decryptions:
- 894 KGB New York to Moscow, 10 June 1943
- 627 KGB New York to Moscow, 5 May 1944
- 864 KGB New York to Moscow, 16 June 1944
- 1053 KGB New York to Moscow, 5 July 1945
- 1182 KGB New York to Moscow, 19 August 1944
- 1508 KGB New York to Moscow, 23 October 1944
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America, Yale University Press (1999), pg. 259, 347, 449.