The rates of CO2 anthropogenic emissions are estimated for Saint Petersburg and Moscow megacities based on satellite CO2 measurements by OCO-2 instrument. The CO2 emission rates for Saint Petersburg amount to 80 and 74 t/km2 per day on March 1, 2016, and May 12, 2018, respectively. The CO2 emission rate for Moscow is estimated as 123, 179, and 186 t/km2 per day for August 25, 2018, June 22, 2018, and March 26, 2017, respectively. The comparison of our results with the estimates for other megacities has shown that the emission estimates for Saint Petersburg are close to those for Los Angeles and Berlin, and estimates for Moscow are close to those for London. The estimation errors are mainly caused by the anthropogenic contribution, which varies from 30% to ~ 90%.