Three studies were conducted to evaluate operator performance with conventional and stereo display systems. The first two studies involved perceptual judgment tasks (a modified Howard-Dolman depth discrimination test and a test of stereopsis, using random dot Julesz patterns), while the third employed a perceptual-motor task requiring end-effector positioning and closure. This third task was designed to approximate the major compo-nents of undersea object recovery missions. In studies One and Two, two methods of displaying stereo information (Fresnel, Field Sequential) were compared. The results of Study One indicate that both of these display systems provide adequate information to enhance performance over that given with a conventional monocular display. Study Two indicates that thresholds of stereo viewing are comparable using the Fresnel system and the Field Sequential system. The data indicate no dif-ference in thresholds over those obtained directly without viewer aids. In Study Three a conventional display was compared with the Field Sequential system used in studies One and Two. The results indicate that the use of stereo cues reduces both response latency and errors significantly. An analysis of performance changes over repeated testing ses-sions indicates significant improvement on both variables. These effects, however, are nondifferential across display systems, and are probably related to the acquisition of manipulator-specific motor-skill learning.