The present study aimed to study the effect of different levels of some antioxidants on post-diluted (PDSM) post- equilibrated (PESM) and post - thaw (PTSM) sperm motility. Also, the effect of these antioxidants on the livability%, acrosomal integrity%, levels of some enzymes as well as on the conception rate was investigated. Semen was collected from five mature Friesian bulls. Good semen ejaculates with at least 70% motility were pooled then split semen fraction was used for experiment. Three levels (0.5, 1.0 and 1.5mM) of each of the antioxidants, zinc methionine (Z-Met.) and seleno- methionine (Sel-Met.) were tested. Six semen fractions were diluted with Tris diluents enriched with the above levels of the
antioxidants, the seventh fraction act as a control. The diluted semen was cooled, equilibrated and packaged in 0.25ml straws and freezed on the surface of liquid nitrogen. After at least 48 hours' storage, straws were thawed in water bath at 38 - 40 ºC for 30 - 60 seconds. Results indicated that, the all levels of the two antioxidants used were exerted a beneficial effect on the all parameters studied with the best PDSM, PESM, PTSM, high mortality and livability %, lower acrosomal damage, least enzymatic leakage and fructose level and the highest conception rate were observed when extended semen was enriched with (1.5 mM) zinc methionine.