In the interocular suppression an image presented in one eye is suppressed when two images from two eyes are dissimilar. For strabismic observers the suppression continuously occurs due to the misalignment of eye positions. In our previous research, the contrast sensitivity under the interocular suppression was measured for normal and the strabismic observers with luminance grating stimuli. In the 15 deg stimulus size condition, we obtained that contrast sensitivity decreased remarkably for the spatial frequency of 2.5 cpd. In the present research, the contrast sensitivity was measured with chromatic grating stimuli in order to investigate whether similar spatial frequency properties were obtained. When the suppression stimulus was a chromatic grating and the detection stimulus was a luminance grating, the contrast sensitivity showed similar properties to those in our previous results. When both the suppression and the detection stimuli were chromatic gratings, the contrast sensitivity decreased for low spatial frequencies, Whereas the suppression stimulus changed to luminance grating, the contrast sensitivity decreased slightly for all spatial frequencies.