Level dry immersion (DI), a model of the physiological effects of microgravity, support deprivation, minimization of muscle activity and proprioceptive afferentation specifically, was used to determine the effects of low proprioceptive, tactile and support afferentation on visual-manual tracking. Hand-eye motor coordination was tested in 13 subjects in 5-d DI who tracked jerky and smooth (linear and pendulum-like horizontal and vertical, circular clockwise and counterclockwise) motions of point visual stimulus. Binocular electrooculography was used to register ocular movements and a joystick with a biological visual feedback to register manual motor acts (1 of 2 stimuli on the screen showed the actual joystick inclination). Computerized stimulation was provided with the help of virtual goggles. Evaluated parameters were latent and total reaction time, amplitude and velocity of eye and hand movements, coefficients of effectiveness (amplitudes ratio) and gain (velocity ratio). Testing was performed before DI, after 3 hours in DI, on DI days 3 and 5, during the first hours and in 3 days after DI (all subjects) and on post-DI days 5-7 (4 subjects). It was demonstrated that support deprivation and minimization of proprioceptive afferentation affect ocular tracking to a larger degree than accuracy of the manual motor act of following the visual stimulus. Manual tracking by all subjects was found more accurate than visual and did not alter significantly during tests sessions; on the contrary, visual tracking accuracy altered noticeably as in the course, so after DI.