The Communicable Disease Surveillance Centre (CDSC) is now firmly established within the new Health Protection Agency (HPA), which was inaugurated on 1st April 2003. In 2002, CDSC celebrated its 25th anniversary. Its achievements over those 25 years, a period when it evolved from a small unit with three staff to an international centre of excellence with over 250 staff, are recalled in this paper. The development of the Centre is reviewed, as are the ways in which it identified and responded to changing patterns of communicable disease over the quarter century. The considerable benefits of placing CDSC within the Public Health Laboratory Service are demonstrated through several examples. The fact that the expansion of CDSC took place during an era when public expenditure was constrained indicates that government valued the service it provided. The elements required and put in place for effective control and prevention of communicable diseases are highlighted and several themes emerge including the close working relationship needed between the various agencies and disciplines, particularly those between epidemiologists, microbiologists and clinicians. Another theme is the commitment to training, (which is necessary to ensure that work is practiCed to the highest standards), as well as to innovation through research and development. A rigorous approach to field investigation is essential, not just to enable the most appropriate control measures to be applied but to increase the knowledge base on infections and the means of prevention. Good surveillance and reference microbiology stand out as the vital components needed to produce the timely and precise information required to influence practice and policy.