There is a need for targeted health promotion aimed at homeless populations. A survey of 100 Big Issue newspaper vendors was conducted, along with in-depth interviews and focus groups, in order to identify health promotion needs. Drug and alcohol problems, the effects of cold weather, nutritional deficiencies, and poor personal hygiene were reported as the main health concerns. However, health was not always an immediate priority for the homeless, with daily concerns predominating, such as shelter and getting money for food. A range of information needs were highlighted and a number of key health promotion topics identified. Social network and social activity data were collected from 14 Big Issue vendors to assess their penetration of groups of homeless people. Both generic and targeted health promotion activities are recommended, and the role of health advocacy and peer education should be further explored.