Sixty-six trials of estrous synchronization were done in buffaloes (31, before superovulation and 35. during superovulation). The donors synchronized before superovulation were injected IM during luteal phase with a single dose of S ml Lutalyse, 5 ml Ilerin or 3.5 ml ProsoMn. Twenty-four hours after luteolytic drug administration, each animal was observed 3 times daily for detecting the onset of the estrus. If the animal was not noticed in estrus up to 5 days after Prostaglandin ( PG) injection, luteolytic drug was repeated again with the same drug and dose, 11 days apart. Response traits for donor included time from treatment to estrus and duration of heat.All donor animals detected in heat were injected IM at mid luteal phase with superovulatory hormones (PMSG). Two days later, the animals received double doses with 12 hours interval of lutalyse (5 ml, each), Ilerin (5 ml, each), or Prosolvin(2 ml each) according to the luteolytic hormone used before superovulation. Synchronization before superovulation indicated that, the mean time for the onset of estrus was 48.25±1.24, 43.83±4.12 and 50.24±1.05 hours, for Lutalyse, Ilerin and Prosolvin, respectively. The mean duration of estrus phase was correspondingly 19.75 ±1.82, 20.17±1.32 and 21.74±1.96 hours. The overall mean lengh of estrus phase was 20.40t0.88 hours. No significant difference between the there treatments. In the synchronization during superovulation, the mean time intervals from treatment to onset estrus was diminished to 31.0±3.03, 22.023.86 and 32.67±4.96 hours for Lutalyse, Ilerin and Prosolvin, respectively.The overall mean was 28.14±2.50 hours. No significant difference for the three treatments on the this criterion. However, the differences between these values before and during superovulation were highly significant (P40.01). Concerning the length of estrus phase, its means were22.2±2.41, 20.0±2.54 and 24.67±3.03 hours for Lutalse, Ilerin, and Prosolvin, respectively. The overall mean length of heat was 21.92±172 hours. No significant differenceses were obsered between the different treatments on the heat duration. Moreover, no significant differences were observed between these values before and during superovulation.