The Navy Primary Standards Department (NPSD) is charged with maintaining and disseminating the fundamental standards of measurement for the U.S. Navy. Measurement areas include Electrical (standard volt and resistance), Microwave, Temperature, Mass, Pressure, Dimensional, Flow and the topic of this paper, Radiometry, Photometry, and Electro-Optics. This paper is divided into four sections. In the first section we describe the primary measurements performed. These include blackbody calibrations, photometric lamp cali-brations, spectral detector, filter and source calibrations, laser power and energy measurements, and optical pyrometry calibrations. Also included in this section are state-ments of the measurement uncertainty. In the second section we describe the primary standards maintained by the laboratory, the process used to maintain traceability to the National Bureau of Standards (NBS), and the processes used to provide the measurement to lower level laboratories. In particular, we discuss fundamental reference standards such as zinc and tin freeze point blackbodies, Measurement Assurance Programs (MAPs), and the use of primary standards calibrated by NBS. We discuss measurement system development in the third section of the paper. Major topics include automation, system standardization, and development of system uncertainties. The principal systems described are a blackbody calibration system, a spectral calibration system to calibrate detectors, filters and sources, and a laser power and energy calibration system. Finally, we discuss the new primary measurements needed to support future Navy requirements. Main topics are near and far field laser beam profile measurements, low light level measurements, high energy laser measurements, fiber optics measurements, and the development of systems that will extend the measurement of electromagnetic radiation to wavelengths of up to one millimeter.