Meningococcal disease is a serious medical condition that can prove fatal within hours in otherwise healthy individuals. Disease incidence is highest in infants, yet there is no broadly protective quadrivalent vaccine that covers this age group. A new investigational quadrivalent meningococcal glycoconjugate vaccine against meningococcal serogroups A, C, W-135, and Y (MenACWY-CRM, Novartis Vaccines, Siena, Italy), has been developed to meet this medical need. This article discusses the vaccine technology behind MenACWY-CRM, focusing on the heritage of CRM(197), the conjugation chemistry, the sizing of the oligosaccharides, and the advantages that these may confer on the vaccine. We highlight the differences between available vaccines and look at the clinical experience with vaccines against other diseases, demonstrating the importance of each component to the immunogenicity of conjugate vaccines. The specific technological approach, including conjugation of meningococcal oligosaccharides of defined length to the CRM(197) protein, has led to a vaccine that has the potential to provide broad meningococcal protection against serogroups A, C, W-135, and Y for all ages.