Abstract: The natural gas in Malaysia is high in CO2 content. The well removal of CO2 from natural gas can be carried out by using physical absorption method. CO2 will be absorbed at high pressure and desorbed at low pressure. The objective of this study was to analyze the phenomenon of CO2 desorption across a venturi nozzle. Dissolved CO2 gas bubble nucleation in water was studied by using CFD simulation. Models regarding bubble nucleation of dissolved gas and solubility in water at different pressure were written in User Defined Function (UDF) to be incorporated into FLUENT. The main parameters that affect the bubble nucleation are the pressure drop across the nozzle and the number of dissolved gas molecules in solution, which is defined by the solubility at the initial condition. The bubble nucleation rate increased exponentially with pressure drop. The highest bubble nucleation was found to be at the wall of the throat of the nozzle. No bubble nucleation can be detected for area with insufficient pressure drop. The bubble nucleation rate profile was similar as the pressure profile across the nozzle.