In the present work, an experimental study for the corynebacterium pseudotuberculosis-inf ection was done in order to elucidate its pathological effects and pathogenesis in guinea pigs, using the strain A Bu 77 isolated from buffaloe cases showing typical lesions of oedematous skin disease. The animals were infected through different routes, skin scarification, intradermal, subcu taneous, intramuscular, oral, intranasal occular, intravaginal, intraurethral and intrarectal, except for skin scarification, intranasal and occular routes, the infective dose was 0.2 ml. of the organism suspension with a viable count of 3 x 10 . According to our results, variation in survival period and severity of infection depend not only on dose and size of the animal, but also on the nature of the infected membrane, vascularity and avialable reticular elements, presence and character of secretion or excre tion at the porta of entry, as well as on the character of this organism to be clumped.