The problem of light scatter from optical surfaces is amplified to a critical level for the optics used in the Ring Laser Gyro (RLG). This has led to the development of a scatterometer at the RLG Lab, Wright-Patterson AFB, which can detect low level light scatter from the high quality optics used in RLG's, without first overcoating with metals. A helium-neon laser is used to illuminate a 0.5 mm diameter spot on the surface of the test part. The incident angle can be varied from 0 to 90 degrees, and the test piece can be maneuvered with five degrees of freedom, four of which are computer controlled. Scatter measurements are made with a photomultiplier detection system which can easily measure down to 10 parts per billion per steradian. The computer can analyze and plot the results very quickly and accurately for further interpretation.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.