Interaction effect of three level of male age broodstock and three type of diluents (distilled water and diluents 1 and 2) for duration of motility and eyed egg rate in rainbow trout (Oncorhynchus mykiss) have been studied. There was no significant difference in activation of sperm by control group (distilled water) in different male ages (p?0.05). Diluents 1, in 3+ year male broodstock has shown, the highest motility (98/4 s) which was significant, comparison to the other male ages. In diluents 2, 3+ year male show highest duration of motility (96/2 sec) in comparison of 2+ and +4 year male broodstock also have showed the highest motility, in comparison to 2+ and 4+ year male whereas, the 2+ year male has the lowest sperm motility. By control group, 2+ year male have shown the highest eyed egg rate (86/8 %) if compared to other male ages. Diluents 1, with 2+ year male age, showed the highest eyed egg rate which was significant, compare to other age groups. Activation of sperm by diluents 2, showed the highest eyed egg rate in 2+ and 3+ year male age broodstock.