One-hundred-and-forty patients diagnosed as having meningococcal disease have been investigated retrospectively with respect to prognostic factors. The overall mortality was 8.6%, the mortality rate of the infants under 6 months of age being higher than that of the other groups. In cases where there was no meningitis or leucocytosis, the presence of hypotension, disturbed consciousness and diffuse petechiae increased the mortality rate significantly. High fever did not have any effect on mortality. We propose a new practical and reliable scoring system for meningococcal disease for determining the influence of prognostic factors on mortality.