Career
Tsvetkov represented Bulgaria in Chess Olympiads. In 1936, at second board in 3rd unofficial Olympiad in Munich (+3 –13 =2);
In 1939, at first board in the 8th Chess Olympiad in Buenos Aires (+7 –5 =4);
In 1954, at fourth board in the 11th Chess Olympiad in Amsterdam (+2 –2 =7);
In 1956, at first reserve board in the 12th Chess Olympiad in Moscow (+3 –1 =5). After World World War II, he played for Bulgaria in some friendly matches: BUL–CSR (1949), BUL–German Democratic Republic (1953), BUL–RUS (1958).
In 1964, he tied for 4–9th in Polanica Zdrój (Rubinstein Memorial).
Tsvetkov was awarded the International Master (IM) title in 1950.