We compared the measurements of the СО2 content in the lower stratosphere (12–18 km altitude layer) using a ground-based Bruker 125HR Fourier-transform spectrometer and ACE satellite measurements in 2009–2019. The analysis of the two types of measurements showed a good agreement between them. On the average, the ground-based CO2 measurements exceed the satellite data by 2.8 ppm (less than 1%), the standard deviations being ∼5.0 ppm. The correlation coefficient between the measurements by the two methods is 0.77. The ground-based and satellite CO2 measurements show weak seasonal variations, opposite to those in tropospheric CO2: the CO2 content in the lower stratosphere is maximal in summer and minimal in winter.