Purpose: This regulation defines the policy and process for establishing and maintaining expert designations under the Corps-wide Centers of Expertise (CX) Program. The program provides an inventory of specialized knowledge and skills within the U.S. Army Corps of Engineers (USACE) that can furnish beneficial and expert assistance to all Corps elements. This regulation also prescribes policy and guidance concerning CX use by USACE major subordinate commands (MSC), districts, laboratories, and field operating activities (FOA). This revision 1) makes the designation Directory of Expertise (DX) obsolete in favor of the designation Technical Center of Expertise (TCX), 2) clarifies when a Center of Standardization (COS) is a Mandatory Center of Expertise (MCX) or a TCX, 3) clarifies the approval process to establish CXs, 4) requires that all CXs currently operating in one capacity or another be recertified within six months of publication of this regulation, and 5) requires all CXs designated as an MCX publish an Engineering Regulation (ER) that provides roles, responsibilities, guidance, and structure of the MCX. The current listing of CXs, including a description of products and services, is available on the USACE Technical Excellence Network (TEN).