Purpose.: We investigated whether the sensory impairments of amblyopia are associated with a decrease in eye position stability (PS). Methods.: The positions of both eyes were recorded simultaneously in three viewing conditions: binocular, monocular fellow eye viewing (right eye for controls), and monocular amblyopic eye viewing (left eye for controls). For monocular conditions, movements of the covered eye were also recorded (open-loop testing). Bivariate contour ellipses (BCEAs), representing the region over which eye positions were found 68.2% of the time, were calculated and normalized by log transformation. Results.: For controls, there were no differences between eyes. Binocular PS (log₁₀BCEA = −0.88) was better than monocular PS (log₁₀BCEA = −0.59) indicating binocular summation, and the PS of the viewing eye was better than that of the covered eye (log₁₀BCEA = −0.33). For patients, the amblyopic eye exhibited a significant decrease in PS during amblyopic eye (log₁₀BCEA = −0.20), fellow eye (log₁₀BCEA = 0.0004), and binocular (log₁₀BCEA = −0.44) viewing. The PS of the fellow eye depended on viewing condition: it was comparable to controls during binocular (log₁₀BCEA = −0.77) and fellow eye viewing (log₁₀BCEA = −0.52), but it decreased during amblyopic eye viewing (log₁₀BCEA = 0.08). Patients exhibited binocular summation during fellow eye viewing, but not during amblyopic eye viewing. Decrease in PS in patients was mainly due to slow eye drifts. Conclusions.: Deficits in spatiotemporal vision in amblyopia are associated with poor PS. PS of amblyopic and fellow eyes is differentially affected depending on viewing condition.