Abstract: CO₂ anthropogenic emissions are estimated for St. Petersburg and Moscow megacities based on OCO-2 satellite CO₂ measurements. The CO₂ emission rates for St. 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 the emission estimates for St. Petersburg to be close to those for Los Angeles and Berlin, and estimates for Moscow to be close to those for London. The estimation errors are mainly caused by the anthropogenic contribution, which varies from 30 to ~90%.