The information provided by HIV surveillance systems is essential for describing current changes in the epidemic and for identifying in a timely manner the geographic areas and subpopulations at greatest risk. In Italy, no national-level HIV surveillance system exists, and only 6 of the country's 20 regions and 3 of its provinces have created local systems. In April 2004 a descriptive investigation of these systems was conducted. The results show extreme variability in their sensitivity and completeness and stress the need to extend systems to all of Italy's regions and to standardise the methods for collecting and transmitting data.