A new computer program has been developed for the simulation of chemical absorption of H₂S and CO₂ using MEA, DEA or hot potassium carbonate. The program can calculate either tray or packed columns. The material and energy balances, and equilibrium relationship are solved using the Naphtali-Sandholm method and the stage to stage method complementarily. The packed column is divided into a number of sections. Each section is treated as a tray, but with a different method of efficiency calculation. The enhancement factor was incorporated to reflect the enhancement of absorption rate which is an inherent nature of chemical absorption. Using this program named as AGRES, 20 sample problems were solved for absorption and stripping and the results were compared with those of other competing programs of AMSIM, PROCESS, ASPEN PLUS and DESIGN II. In the calculation of ideal stages, all the programs gave similar results. In the calculation of real stages, however, only AMSIM and AGRES were effective. AMSIM could not calculate packed columns and tray columns having more than 22 stages. While, AGRES could overcome this limitation of AMSIM, providing a broader application.