Since the Global HIV Surveillance meeting in Addis Ababa in 2004, countries have expanded and improved their surveillance systems in line with the recommendations of that meeting. In addition, more elaborate and comprehensive analyses are being done using surveillance data as well as other sources to inform the HIV response. This paper presents examples of data use from four countries with different HIV epidemics. Each example describes the sources of data, the methods for analysis, the results and the actions that came as a consequence of those data. The examples from Bangladesh, Nigeria, Kazakhstan and Rwanda show the importance of combining data from a variety of sources when planning or evaluating HIV programmes. The conclusions discuss the importance of using multiple sources of data, collaborating with programme managers, and sharing results with all possible beneficiaries from local level to global level.