BACKGROUND: A number of countries worldwide have structured horizon scanning systems which provide timely information on the impact of new health technologies to decision makers in health care. In general, the agencies that are responsible for horizon scanning have limited resources in terms of budget and staff. In contrast, the number of new and emerging health technologies, i.e. pharmaceuticals, medical devices, and medical and surgical procedures, is growing rapidly. This requires the Horizon Scanning Systems (HSSs) to devise efficient procedures for identification of new health technologies. The role of the Internet for this purpose has as yet not been documented. OBJECTIVE: To describe and analyse how the Internet is used by horizon scanning systems to systematically identify new health technologies. METHODS: A questionnaire was developed and distributed among 10 agencies known to work within this specific area. The questionnaire specifically focussed on type of sites scanned, frequency of scanning, and importance of a site for the identification of a new health technology. RESULTS: A 100% response rate was obtained. Seven out of 10 agencies used the Internet to systematically identify new health technologies, of which 6 provided complete information. A total of 110 web sites were scanned by these 6 agencies. The number of sites scanned per agency ranged from 11 to 27. Most sites were scanned weekly (41%) or monthly (33%). Thirty-one percent (31%) of the total number of sites was considered as highly important. The agencies spent at least 2 hours a week and at most 8 hours per week scanning the Internet. Although each agency's remit differed somewhat in scope, on average the same types of sites were scanned. These include sites from regulatory agencies, sites with information on new drugs or new devices, and sites with news from newswires. However, within these types there was not much correlation between the individual sites that agencies judged important to scan. CONCLUSION: The use of the Internet for identifying new health technologies is increasing in the majority of horizon scanning systems around the world. At the same time there is considerable variation between individual agencies in their approach to this source of information. This can only be partially explained by differences in scope of scanning activities of the individual agencies. A coordinated effort to develop Internet search strategies for either different categories of health technologies or different clinical specialties may improve efficiency and quality of scanning in terms of the number of potentially relevant technologies identified.