Energetic and structural heterogeneity of three synthetic carbons was studied on the basis of low-temperature nitrogen adsorption isotherms measured over the entire pressure range. A special emphasis was placed on the measurement and analysis of adsorption data at very low pressures. The resulting adsorption isotherms were used to perform the standard characterization of the carbons studied, which included the evaluation of the BET specific surface area, the external surface area, the total pore volume, and the micropore volume. The primary objective was to determine the adsorption energy distribution and the micropore size distribution from the low-pressure adsorption data for the synthetic carbons studied and compare them with the corresponding distributions for a regular active carbon.