A computer model for simulating the kinetics of dissolution of CaCO3, CARKIN-1, is presented and partially validated with experimental data. Carbonate reactions in the aqueous phase are described in the model by chemical equilibria and equations defining ionic strength, ionic activity, carbon mass balance, charge balance, and calcium mass balance. Physico-chemical processes at the interface between the gaseous and liquid phases and the interface between the liquid and solid phases are described in the model by time-dependent reactions. The rate of CaCO3dissolution is defined by a partial differential equation similar to the Reddy-Nancollas model for precipitation. The rate of exchange of CO2gas at the gas-liquid interface is defined by a second partial differential equation that incorporates Fick's law of diffusion, Henry's law, and the rate of change of total aqueous carbon.Data to validate the model are from a “free-drift” laboratory dissolution study with reagent grade powdered CaCO3and silt-sized Iceland spar at undersaturated to saturated equilibrium concentration levels and several ranges of CO2pressure at 25°C. CARKIN-1 demonstrates the potential to simulate dynamic changes in pH and Ca ion activity. Sensitivity of several model parameters is illustrated. The surface area of CaCO3, which is not currently considered explicitly in the model, is clearly an important variable.