Foot and mouth disease (FMD) is a contagious disease of cloven-hoofed animals including cattle, buffaloes, sheep, goats and pigs with economic impact due to losses of production, reduced milk yield and abortion. Control of FMD is widely depending on vaccination. This work aimed to evaluate an inactivated trivalent FMD vaccine prepared using Montanide ISA 201 adjuvant applied in sheep. The prepared vaccine was sterile, safe and induced protective neutralizing antibody titer from the second week post vaccination (wPV), reached the highest level at 12th wPV and persisted in protective level till 40 wPV for FMD virus serotypes O, A and SAT2. These results were confirmed using ELISA. Evaluation of FMD virus-specific cell-mediated immunity in sheep vaccinated using XTT assay showed a high lymphocyte proliferation expressed by optical density in vaccinated sheep group from the 3rd day post vaccination (dPV), increased to reach a maximum value 2nd wPV and persisted in a high level till 9th wPV for FMDV types O, A and SAT2 inducers. It was concluded that the prepared inactivated trivalent FMD vaccine with ISA-201 adjuvant induced good humoral and cellular immune responses in sheep lasted for 40 wP