The increase of CO2 caused by climate change has been forecasted in the coming years. The elevated CO2 in water could affect on the aquatic animals. This study examines the effects of high CO2 in water on developmental stages of black tiger shrimp (Penaeus monodon). Four triplicated treatments of CO2 concentrations including 1.76mg.l-1 (control, equal to pH 8.2); 7.02mg.l-1 (pH=7.6); 17.6mg.l-1 (pH=7.2); and 44.3mg.l-1 (pH=6.8) were conducted to observe the development of embryonic, larval, and post-larval stages. The fertilized eggs were directly incubated in selected pH levels. The hatching rate was highest (93.8%) at 1.76mg.l-1 CO2; and significant difference (p