Low libido and semen quality of bulls often occur resources semen that can decrease the efficiency of reproduction, thus affecting food security. This study aims to evaluate the role of the mineral zinc in the Moringa oleifera (M.oleifera) leaves to increase the libido and semen quality of Bali bulls. Two Bali bulls were reared for three periods, each period of eight weeks. The first period (control), fed with concentrates 1% of body weight and rice straw ad lib. The second period (given M.leifera leaves), fed with equal to the first period plus M.oleifera leaves 15% of the weight of the concentrate. The third period (given Zn), fed with equal to the first period plus Zn equivalence Zn content of the M.oleifera leaves in the second period. The libido and semen quality measured twice a week. The M.oleifera leaves and Zn significantly (P<0.05) increase libido (331.75 vs 192.75 vs 152.00 seconds), volume of semen (2.71 vs 3.78 vs 4.19 ml), total sperm motility (57.38 vs 91.22 vs 89.37%), and progressive sperm motility (58.14 vs 77.12 vs 76.4%), but not indicate a significant the difference (P>0.05) between M.oleifera leaves with Zn, while the concentration of sperm (871 vs 1,091 vs 969 million/ml) did not show a significant increase (P>0.05). Sperm bulls who were given M.oleifera leaves and Zn has characteristics motility significantly higher (P<0.05) than control, but shows no significant the difference (P>0.05) between the M.oleifera leaves with Zn. The M.oleifera leaves and Zn to restore libidinous Bali bulls and increase the volume of semen, total motility and progressive motility of sperm as well as occurring hyperactivation so to increase fertility. This result indicates that the zinc in the M.oleifera leaves had a role increase the libido and semen quality of Bali bulls. Keywords: Zn, Moringa oleifera, libido, semen quality, Bali bulls.