The primary objectives of the 2007-08 THMIS survey were to provide up-to-date information on the prevalence of HIV infection among Tanzanian adults, and the prevalence of malaria infection and anaemia among children under age five years. The findings will be used to evaluate ongoing programmes and to develop new health strategies. Where appropriate, the findings from the 2007-08 THMIS are compared with those from the 2003-04 Tanzania HIV/AIDS Indicator Survey (THIS). The findings of these two surveys are expected to complement the sentinel surveillance system undertaken by the Ministry of Health and Social Welfare under its National AIDS Control Programme (NACP). The THMIS also provides updated estimates of selected basic demographic and health indicators covered in previous surveys, including the 1991-92 Tanzania Demographic and Health Survey (TDHS), the 1996 TDHS, the 1999 Reproductive and Child Health Survey (RCHS), and the 2004-05 TDHS. More specifically, the objectives of the 2007-08 THMIS were: To measure HIV prevalence among women and men age 15-49; To assess levels and trends in knowledge about HIV/AIDS, attitudes towards people infected with the disease, and patterns of sexual behaviour; To collect information on the proportion of adults who are chronically sick, the extent of orphanhood, levels of and care and support; To gauge the extent to which these indicators vary by characteristics such as age, sex, region, education, marital status, and poverty status; and To measure the presence of malaria parasites and anaemia among children age 6-59 months. The results of the 2007-08 THMIS are intended to provide information to assist policymakers and programme implementers to monitor and evaluate existing programmes and to design new strategies for combating the HIV/AIDS epidemic in Tanzania. The survey data will also be used as inputs in population projections and to calculate indicators developed by the United Nations General Assembly Special Session (UNGASS), the UNAIDS Programme, and the World Health Organization (WHO).