This paper describes laboratory evaluations ofthe SAAO Adaptive Optics (AO) System, which is installed at the Air Force AEOS facility at Haleakala on the island ofMaui in Hawaii. The AO system includes a 32x32-channel wavefront sensor, a high-speed wavefront reconstructor, a 94 1-actuator deformable mirror, a high-bandwidth steering mirror, and a tracking sensor for tilt control. The performance metrics discussed include track bandwidth, trackjitter vs. target brightness, AO system temporal response, and the resulting Strehl ratios and MTF for a range oftarget brightnesses. Test methods and results are described.The SAAO adaptive optics system underwent acceptance testing at the Raytheon factory in Danbury, Connecticut, in February and March of 1999. A full description ofthe system can be found in the paper "The SAAO Adaptive Optics System," included in this proceedings. This paper briefly describes the testing and the measured performance ofthe SAAO adaptive optics system. Mission analysis performed by the Air Force team responsible for the procurement ofthe AEOS facility set the requirements for imaging performance. These requirements took the form of a set of MTF curves. The curves were generated from detailed system models, using as inputs the basic parameters ofthe main telescope, and a statistical representation ofthe expected atmospheric disturbance prevailing at the site. The disturbances were a Fried "coherence length" rO of 5 centimeters evaluated at 750 nanometers, and a Greenwood frequency2 of 122 Hz, with a 45 degree elevation angle measured from the zenith.The production ofphase disturbance optics (phase plates,) to be used as a physical test input disturbance, and that would faithfully represent the statistical parameters ofatmospheric disturbance stated above, was abandoned early in the program as a cost-saving measure. It was decided that performance assessment would be obtained by heavy reliance on a full-up system model (proprietary to Raytheon,) the behavior of which would be anchored to the hardware. (A description ofthis model is included in the paper "Modeling ofthe SAAO Adaptive Optics System," also included in this proceedings.) The closed-loop behavior of the model was to be tied to the actual hardware by means ofmeasuring bandwidths and phase margins of the actual hardware under certain conditions, using an on-board test light source (the OSS; see "The SAAO Adaptive Optics System" in this proceedings for a description) and applying the measured values to the In Gas, Chemical, and Electrical Lasers and Intense Beam Control and Applications, Santanu Basu,