The purpose of this paper is to describe the development and features of a revised computerized adaptive testing (CAT) item pool creation system. This system refines and upgrades the system that is currently in use for the ongoing creation of CAT pools for several large-scale, high-stakes testing programs administered by Educational Testing Service (ETS). Using data from a large-scale CAT program administered by ETS, an illustrative application of the software is provided to compare pools created using simultaneous partitioning and sequential partitioning. The results of the comparison indicated that simultaneous partitioning was preferable to sequential partitioning in the conditions studied. The paper concludes by identifying and discussing several issues that remain to be investigated in utilizing the revised pool creation system with ETS CAT programs.