This experiment aimed to evaluate the effect of PGF2α and time of injection on the quality and viability of Local ram sperm in Tris dilution at 50C storage temperature. The sperm was collected from four Local rams with artificial vagina, once a week for one month. At the first week, sperm were collected without PGF2α injection; 10 minute after PGF2α injection in second week; 20 minute after PGF2α injection in third week; and 30 minute after PGF2α injection in fourth week. PGF2α with dose of 1,0 ml/head (7,5 mg Luprostiol/ml) were given by intramuscular injection in thigh area. The data were analyzed by Completed Randomized Design. When there were significant differences continued with Duncan’s New Multiple Range Test. The result showed that PGF2α injection significantly (p0.05). Based on the result of this study, it was concluded that PGF2α injection 10 minute before sperm collection could improve sperm quantity and quality specifically sperm motility and sperm life percentation.