It is widely believed that homeless people place considerable demands on emergency hospital services, but quantifying this in a systematic way has proved difficult. The primary purpose of this paper is to develop a better empirical understanding of the nature and extent of unplanned admissions to acute hospitals in London by homeless people. Data was collected about the distribution of different types of homeless people in London and attributed to the 28 district health authorities. The authors say that the full impact of unplanned hospital admissions amongst homeless people cannot be captured adequately by the bald statistics contained in this document. An assessment of all the financial and organisational effects requires more detailed research about the implications of treating large groups of homeless people. Consideration of these findings, in the context of a broader review of the problems of homelessness, suggests that a new approach to policy and practice is badly needed in relation to housing policy, the planning of health services, and NHS resource allocation.