Temporal contrast sensitivity functions were determined for the normal (20/20) and amblyopic eyes of five strabismic and/or anisometropic amblyopes and for both eyes of two nonamblyopes. In deep amblyopia (20/100+), contrast sensitivity was reduced at all temporal frequencies in the amblyopic eye, whereas no deficit was observed for subjects whose acuity was 20/40 or better. This result indicates that reduced temporal sensitivity is a significant component of strabismic and anisometropic amblyopia.