Large-scale simulations of aluminosilicate zeolites were conducted to identify structures that possess large CO2 uptake for postcombustion carbon dioxide capture. In this study, we discovered that the aluminosilicate zeolite structures with the highest CO2 uptake values have an idealized silica lattice with a large free volume and a framework topology that maximizes the regions with nearest-neighbor framework atom distances from 3 to 4.5 ̊. These predictors extend well to different Si:Al ratios and for both Na+ and Ca2+ cations, demonstrating their universal applicability in identifying the best-performing aluminosilicate zeolite structures. © 2012 American Chemical Society.