Meningococcal infections still kill more than a million people a year across the world despite the fact that the bacteria are generally sensitive to antibiotics. Lack of vaccines to some strains and the rate at which the infection progresses are key to this problem. We are using structural biology to study how the bacteria attempts to evade the human immune system and then use the information gained to improve vaccine design. Recent work focusing on evasion of the human complement system will be presented