Amblyopia is a common childhood vision disorder with a prevalence of 1.6-3.5% worldwide. It has different causes such as anisometropia, strabismus and visual deprivation. This study aimed to determine the effect of patching operation of the better eye on visual acuity (VA) and contrast sensitivity function (CSF) of the amblyopic eye. Thirty four children (18 boys; 16 girls) with mean age of 6.88-1.48(SD)yearsparticipated in the study. Twenty six children had anisometropic and eight had combined (anisometropia and strabismus) amblyopia. VA and CSF of the subjects were measured through YANG vision tester before and three months after patching therapy.The VA between both eyes and CSF at four spatial frequencies, 1.5,6, 12 and18 cycles per degree (cpd) in two phases, were compared. In the better eye, the best corrected VAdid not show any significant difference before and after treatment. In amblyopic eyes, postoperative VA significantly improved (P<0.001). Furthermore, the postoperative CSF at high and low spatial frequencies did not show statistically significant difference, whereas at the medium levels significantly increased(P=0.003, 0.001).VA increased in 64% participants and CSF improved 1.16, 1.57, 3.91 and 2.44 times in 1.5, 6, 12 and 18 spatial frequencies respectively. Complete (VA 20/20) and relative improvement (at least 2 lines) of VA was achieved in 60.61% and 39.39% of amblyopic cases respectively. Based on our results, patching of the better eye in amblyopic children can improve VA and CSF, especially in intermediate frequencies. Therefore, our findings recommend the CSF as an accompanying and complementary test for VAat pre and post patch operationevaluation in amblyopia treatment.