Carbon spheres for CO2 adsorption were prepared using a modified Stöber method in a microwave assisted solvothermal reactor. For comparison purposes, the same preparation procedure was applied in an autoclave. A starting mixture composed of water-ethanol, ammonia water, EDA, resorcinol, potassium oxalate and formaldehyde, was stirred for 24 h at room temperature and then subjected to a pressure treatment in an autoclave (24 h at 100 o C) or in a microwave solvothermal reactor (15 min under 2 MPa). The material with EDA prepared in the solvothermal reactor exhibited high CO2 adsorption capacities, up to 5 mmol/g under ambient conditions and 6.6 mmol/g at 0  o C.