Cell culture assays are possible alternatives to replace in-vivo neutralization tests currently required for potency testing of clostridial vaccines. So, the objective of this work was to titrate C. perfringens type A alpha vaccine in Vero (African Green Monkey Kidney) cells and standardize an in-vitro seroneutralization test to evaluate the potency of the alpha toxoid by comparison with the animal bioassay. The present work revealed that alpha toxin of C. perfringens type A, has a characteristic cytopathic effect (CPE) on African green monkey kidney cell line (Vero) represented by retraction and cell rounding. Vero cells can be used for titration of such toxin where the CPE of a prepared toxin was determined up to a dilution of 1:800 (using 50ul for tissue culture inoculation) while the minimum lethal dilution of the same toxin in mice was found to be 1:40 (using 100 ul for mice inoculation) revealing the high sensitivity of Vero cells. The Testing potency of a prepared hyperimmune serum and nine C. perfringens type A vaccines through application of serum neutralization test (SNT) in Vero cells and mice showed that there was no significant difference between the two tests. Therefore, these cell culture assays could be suitable in-vitro alternatives to in-vivo mouse neutralization experiments required for potency tests of C. perfringens type A vaccines to save time, cost, effort and avoid the use of live animals.