We examined oculomotor responses to binocular disparities of one stereo-normal and three stereo-anomalous observers, who were identified through a stereoscopic depth-discrimination task, in two experimental conditions. In the pulse disparity condition, crossed and uncrossed disparities (1-6°) were briefly presented (for .25-2.0 s). In the ramp disparity condition, disparities were varied continuously with constant velocities (.7-2.0°/s) and with an amplitude of 10°. The stereo-normal observer showed vergence responses to both pulse and ramp disparities. The three stereo-anomalous observers showed a marked reduction or absence of vergence responses to pulse disparities but showed vergence responses to ramp disparities. The results suggest the existence of separate sub-systems mediating disparity vergence eye movements.