The Laser Wavefront Analyzer (LWA) determines the intensity and phase of a CO2 laser operating over a spectral range from 9.1 pm to 10.7 pm. The LWA is a sliding reference interferometer and measures differential optical phase over a 32 x 32 element format of the input beam. A resolution element is scanned every 10 ptsec. The theory and general design aspects of the LWA are discussed in this paper. Phase and intensity data outputs obtained with the instrument during calibration tests performed by the Air Force Weapons Laboratory at Kirtland Air Force Base are presented. These calibration data were obtained by utilizing low power CO2 gas lasers with appropriate optical components to magnify and alter the phase front of the beam entering the analyzer sensor aperture. Phase accuracy and precision data from these calibration tests are also presented.