Waterborne coatings are preferred to the solvent-based because they are environmentally sound. In waterborne coatings, blends of two or more latex components of different characteristics recently attract attention as a method to give desirable properties such as gas permeability and elasticity. In this study, we cast latex blend films from the mixtures of a high Tg latex and a low Tg microgel of crosslinked core/shell structure and investigate the effect of amount of microgel on CO₂ and water vapor permeability and mechanical properties of the films.