This study aims to determine the proper dose and route for vaccination of sheep against foot and mouth disease (FMD), by using trivalent oil FMD vaccine in addition to gaining the highest protective antibody titers. Six groups of sheep (6 sheep / each) were vaccinated with different doses of the trivalent oily FMD vaccine [full (1.5 ml), ½ (0.75ml) and ¼ (0.37ml) doses], S/C or I/M. The experiment included challenged non-vaccinated control group (2 sheep for each used Viral strain). Pre- vaccination blood samples of all groups then weekly blood samples were collected to follow up the level of induced antibody titers by using SNT and ELISA. Four weeks post vaccination all animal groups were challenged by inoculation intradermolingual (IDL) with 10.000 ID50(infective dose fifty) sheep adapted FMD (O & A & SAT2 types) virus and subjected to clinical observation for 8 days. The results showed that the vaccinated animals with a full and ½ dose injected either S/C or I/M were able to withstand the virus infection while animals vaccinated with ¼ dose didn't. The vaccinated group given full dose through S/C route showed the highest protective antibody titers against all viral strains of the vaccine.