A set of standardized and realistic aftertreatment catalyst testing protocols have been developed in support of the U.S.DRIVE Partnership. The protocols are intended to enable the accurate evaluation and comparison of aftertreatment catalyst performance data from various testing and research facilities to maximize the impact of discovery-phase research occurring across the nation, thereby accelerating the pace of exhaust aftertreatment catalyst innovation. The protocols address a need identified by the Partnership’s industry partners for consistent and accurate metrics for aftertreatment catalyst evaluation and comparison. The protocols consist of a set of standardized requirements and test procedures that sufficiently capture the performance capability of a catalyst technology in a manner that is adaptable in various laboratories. This article details four low-temperature catalyst testing protocols applicable to (1) oxidation catalysts, (2) passive storage (and release) catalysts, (3) three-way catalysts, and (4) NH3-SCR catalysts.