Infrared radiometers for irradiance measurement have been developed at the National Institute of Standards and Technology (NIST). These high performance irradiance meters are used to realize and maintain the spectral irradiance responsivity scale between 1000 nm and 5000 nm. They are also working standards that disseminate the infrared irradiance responsivity scale to other institutions and facilities. Both design considerations and responsivity scale transfer to the irradiance meters are discussed. The radiometers were calibrated for spectral irradiance responsivity on the new NIST Infrared Facility for Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (IR-SIRCUS). The spectral irradiance responsivity calibrations described are derived from absolute cryogenic radiometers.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.