The objective of this study was to determine the effect of the different ratio of young coconut water and egg yolk extender and length of storage at low temperature on sperm motility and viability of Bali bull. The method used was an experiment in the completely randomized factorial design. The first factor was young coconut water and egg yolk ratio which consisted of 5 treatments, including P0 (control) = Tris aminomethane, P1 = 85% of young coconut water + 15% of egg yolk, P2 = 80% of young coconut water + 20% of egg yolk, P3 = 75% of young coconut water + 25% of egg yolk, P4 = 70% of young coconut water + 30% of egg yolk. The second factor was the length of storage at a low temperature which consisted of 3 treatments, including 1 day, 2 days and 3 days. All treatments were replicated 10 times. Variable measured was sperm motility and viability. Results showed that the sperm motility of Bali bull in P0 (control) after 3 days of storage was 38.00%, which was significantly different (P<0.05) compared to P1 (21.50%), P2 (24.50%), P3 (28.00%), and compared to P4 (33.50%). Results also showed that sperm viability of Bali bull in P0 after 3 days of storage, which was in the amount of 65.06%, was significantly greater (P<0.05) than P1 (55.64%), P2 (58.42%), and P3 (60.91%), but did not significantly different (P>0.05) compared to P4 (63.54%). The conclusion of this study is that the use of extender which composed of 70% of young coconut water + 30% of egg yolk could maintain the sperm motility and viability of Bali bull. KEY WORDSCoconut water, egg yolk, length of storage, sperm motility, Bali bull.