For the treatment of strabismic amblyopia the authors have used atropine in the sound eye under usual optical correction as soon as central fixation of the amblyopic eye is secured by means of proceeding occlusion therapy. Although there may be little effect of occlusion in atropine therapy, six children under five years of age developed amblyopia in their sound eyes. In every case, the first sign of developing amblyopia was the decrease of fixation ability in the sound eye in a binocular fixation test prior to the reduction of visual acuity. On the other hand, fixation ability of the originally amblyopic eye was reinforced more and more not only during atropinization but after its finish until deep amblyopia developed in the sound eye. In three cases, eccentric fixation occurred at 7, 9, and 17 weeks after atropinization. These facts suggest that occlusion amblyopia following atropine therapy is not the result of deprivation but is due to the reversal of the eye used for fixation. Strabismic amblyopia may have the tendency toward an alternation between fixation abilities of the two eyes and such a binocular sensory anomaly may cause strabismic amblyopia itself.