Experiments were carried out to find the optimal conditions for the replication of BHK 21 C 13 cells in one 1 roller glassware with the use of a nutrient medium containing products of the enzymatic breakdown of white of egg. Studied was the sensitivity of these cells to the type C strain 'Hungary' of the foot-and-mouth disease virus. Two series of F. M. D. vaccines were produced, which proved to be sterile and innocuous for guinea pigs. Immunogenicity trials with regard to these animals revealed that the VD50 (vaccinal dose) values ranged from 0.12 to 0.26 cm3.