The solubility of carbon dioxide in aqueous HCl and NaHCO3 Solutions has been determined by the coulometric technique at ambient pressure and at 278, 283, 287, and 298 K. The maximum molality of HCI and NaHCO3 solutions was 1 and 0.5 mol-kg(-1), respectively. The error in CO2 solubility in HCI solutions estimated from parallel experiments was about 0.3%. For bicarbonate solutions, the overall error was larger because the solubility is the difference between the determined dissolved inorganic carbon and sodium bicarbonate molality. Under investigated conditions, errors in solubility data varied from 0.3% for dilute solutions to ± 1.3% for 0.5 m sodium bicarbonate. Obtained data were treated by the Pitzer method. Pitzer parameters ℷ(CO2,NaHCO3) and ℷ(CO2,HCI) were derived as a function of temperature.