Outbreaks of meningococcal disease were observed for the first time in the Israel Defence Force (I.D.F.) in 1992 and 1993, while in previous years, cases appeared in sporadic fashion. Two episodes in the winter of 1992 involving three and two individuals, respectively, were caused by Neisseria meningitidis group C, which was nontypable and nonsubtypable (C:NT:-). Three cases in one event in early 1993 were due to group C:NT:P1.2, the two secondary cases being caused by strains completely resistant to rifampicin. While these outbreaks were small, they should be seen against a background of the emergence of relatively virulent clones of serogroup C which have caused significant outbreaks in several countries. This and the drug resistance problem will require medical decision-makers to review strategies for the prevention of meningococcal disease, taking into account alternative agents for chemoprophylaxis as well as a possible role for vaccination.