The outer membrane of Neisseria meningitidis contains a variety of proteins with the potential for inclusion in new meningococcal vaccines (1 ). Studies on the vaccine potential of these proteins would be facilitated by the production of pure recombinant protein, free from other components of the Neisseria outer membrane. At present, the class 1 outer-membrane protein (OMP) is generally regarded as the most promising candidate. In this chapter, we describe four protocols involved in the preparation of recombinant class 1 OMP for vaccine development. This integrated set of methods can also be readily used to study the potential of other meningococcal OMP as vaccine candidates, and moreover, their utilities make them attractive for vaccine studies relating to many other human pathogens.