The IOC said all four - Victoria Valyukevich, a triple jumper who was eighth in the women's competition, hammer throwers Gulfiya Khanafeeva and Mariia Bespalova, and weightlifter Khadzhimurat Akkaev, who did not compete due to a back injury, had tested positive for anabolic steroid turinabol.
The disqualification means they are stripped from London 2012's records. Valyukevich, having come in eighth, will also have to return a diploma she received for her finish.
More than 100 athletes have so had positive results in re-tests of samples taken during the London and Beijing 2008 Olympics conducted by the IOC.
The re-testing programme is part of the IOC's efforts to catch cheats using newer testing methods or looking for substances that were not known at the time of past Olympics and prevent them from competing in future Games.
Samples are stored for a decade, and for the 2008 and 2012 re-tests Russia has had the most positive cases per nation.
Russia saw virtually its entire track and field team banned from the 2016 Olympics in Rio de Janeiro as a result of a widespread national doping scandal that implicated sports officials, coaches, doctors and more than 1,000 athletes from many sports.
Read the original article on Eurosport: IOC disqualifies four Russians from London Olympics over doping