In the present work, new experimental data are presented on the solubility of carbon dioxide in aqueous piperazine solutions, for concentrations of 0.2 and 0.6 molar piperazine and temperatures of 25, 40, and 70 degrees C respectively. The present data, and other data available in the literature, were correlated using a model based on the electrolyte equation of state (EoS), as originally proposed by Furst and Renon. The final model derived, containing only seven adjustable (ionic) parameters, was able to describe the available experimental solubility data (> 150 data points for total and/or CO2 partial pressure) with an average deviation of 16%. (c) 2005 American Institute of Chemical Engineers