Since 2017, the NBL Program Office has continued its role as a reference material producer (RMP) in accordance with the requirements defined in the ISO standard 17034 General requirements for the competence of reference materials producers . The NBL PO has developed and implemented a quality system based on the ISO standard, and it collaborates with DOE’s national labs and other collaborators for the actual laboratory measurements, which meet the requirements of ISO/IEC 17025 Testing and calibration laboratories . Recently, the NBL PO entered into an interagency agreement (IAA) with the National Institute of Standards and Technology (NIST). The collaboration with NIST is designed to bring the NBL PO’s certified reference material (CRM) development into close alignment with NIST’s CRM planning, experimental design, data evaluation and certification practices. Implementation of the IAA involves NIST consultation and review of the NBL PO’s planning and design documents for each CRM project. In some cases, the NBL PO will employ NIST’s Statistical Engineering Division for measurement data analysis and uncertainty estimation. Several CRM projects are proceeding within the NBL PO – NIST collaboration. They include Pu isotopic standard C137A, a Pu metal standard to be produced in FY23, an update to the uranium assay value in CRM C112A and several nuclear forensics materials. Details of how the NBL PO is interacting with select national labs for these projects, the interactions with NIST will be described in this presentation.