Lord Macpherson's definition of institutional racism was central to his report about the police investigation into the murder of Stephen Lawrence. It was also integral to his recommendations for the reform of the police in England and Wales. Lord Macpherson argued for changes to race relations within constabularies. His notion of institutional racism is scrutinized in this article, based on evidence from a two-year project about Black Police Associations in the United Kingdom. Different meanings of institutional racism and their consequences are discussed, the locus of racism is charted, and the importance of an institutional memory of racism within constabularies is emphasized.</p