The performance of the absorber determines the COP of the absorption chiller. This paper deals with the heat and mass transfer characteristics for a falling film type absorber when non-absorbable gas lair) is present in the gas side. The study is based on a mathematical model which describes the heat and mass transports for the absorption process taking place on a falling wavy film flow. The results are compared with that of smooth film absorption as well as the results of wavy film absorption without the presence of non-absorbables. It is shown that wave enhances the absorption rates while the non-absorbables depress, the absorption rates significantly. The present simulation is found to be in good agreement with previous experimental results. The correlations for heat and mass transfer coefficients are given.