The present study was carried out to observe inter-strain variation at molecular level in the two vaccinal types (B:3,4 and B:6) of Pasteurella multocida. The micro-organisms were identified and characterized by using conventional microbiological tests. The results of these tests were unable to show any definite variations between the two vaccinal strains studied. Whole cell SDS-PAGE profiles showed similarities in the two vaccinal strains. However, SDS-PAGE profiles of envelope showed differences between the two vaccinal strains.  The 85, 27 kDa major and 70, 40 kDa minor proteins were common in both strains, while the 50, 32 and 29 kDa major proteins were found in B:3,4 but absent in B:6. SDS-PAGE profiles of outer membrane protein (OMP) showed that 26 minor bands were common. The 50 and 32 kDa major proteins were found in B: 3,4 and absent in B:6, while 46 kDa minor protein was found in B:6 only. So, the present study concluded that the two vaccinal strains of Pasteurella multocida had differences in OMP, lipopolysaccharides and whole cell extracts

Key words: Vaccinal strains, Pasteurella multocida, SDS-PAGE.