The effect of L-tyrosine on anestrus buffalo-cows were examined. A single oral dose of L-tyrosine (100 mg/Kg b.w.) were given for 48 buffaloes suffering from ovarian inactivity, beside another five animals, kept untreated (control). The results revealed that 42(87.5%) buffalo-cows came to heat within 6-9 days after treatment. Twenty-eight of them proved to be pregnant at day 42nd post service. The progesterone level in anestrus buffalo-cows pretreatment was lower than 0.2 ng/ml. Higher values for progesterone were estimated in the treated buffalces (1.7 ng/ml) than in the control ones (0.16 ng/ml) (P/0.01). Highly significant difference (P/0.01) was found in the progesterone level in the pregnant buffaloes than in the control at the same period (3.40 ng/ml and 0.16 ng/ mi respectively). The results indicated that a single oral dose (100 mg/kg b.w.) of L-tyrosine could induce the estrus in anestrus buffaloes.