An outbreak of group A meningococcal infection amongst the Muslim population in England followed the outbreak of meningococcal disease associated with the 1987 Haj to Mecca. There were 18 primary cases amongst pilgrims returning from Mecca and 15 subsequent cases among Muslims over the following 19 months. The meningococcal strains were shown to be of the same clone as strains from the Mecca outbreak by possession of an outer membrane protein PI.9. Strains of this group A clone (A III-I) had only rarely been encountered in England before this outbreak.