By means of a model experiment the possibility of preserving a N. meningitidis strain by freezing was demonstrated and verified. The results of cultivating the strain after storage at - 20 degrees C, - 15 degrees C and +4 degrees C for 4, 6, 24 and 48 hours were compared. The temperature of - 20 degrees C was found to be the most reliable one for preserving the viability of the N. meningitidis strain. The method of freezing the strain is of practical importance under conditions where no low-freezing box or liquid nitrogen are available.