Between 1976 and 1984 he claimed seven gold and five silver medals at the Summer Olympics and World and European championships.

His last snatch world record was 195.5 kg in the 90 kg weight class, set on 1 May 1983 in Varna and remains the heaviest weight ever snatched by a middle heavyweight.

He represented his native country Bulgaria at the Summer Olympics in Montreal (1976) and in Moscow (1980).

He won a silver Olympic medal in the light heavyweight 1980 after being stripped of the silver medal in the -82.5 kg competition in 1976 Summer Olympics due to a positive steroid test.

Blagoev also won three consecutive World Cups in Varna, Bulgaria in 1982-1984 and 5 Bulgarian Championships (1979, 1981-1984).