The national adult HIV prevalence for Zambia is estimated at 16% with proportions of 18% for women and 13% for men. HIV prevalence ranges between 8% and 22%, with urban rates being about two times higher than the rural rates. About 900,000 Zambians are living with HIV/AIDS and an estimated 1.1 million orphans have either lost both or one parent largely due to AIDS mortality. This paper discusses the tools and methods used to measure HIV/AIDS and its socioeconomic impact on the Zambian population. The major data sources include population based surveys of Census, Living Conditions Monitoring Surveys, Sexual Behaviour Surveys and Demographic and Health Surveys; Sentinel Surveillance for pregnant women and high risk populations; and using estimates and projections techniques. Overall results show that HIV has spread to all parts of Zambia and very high prevalence levels of HIV are found in urban areas. Worse still, HIV affects mostly men and women in their prime and productive age groups of 25-39 years and all sectors of the Zambia society. Socio-economic impacts have been felt at both micro levels (individual households and community) and macro level (the nation as a whole). These data sources have helped to evaluate the effectiveness of various HIV/AIDS intervention programs and have also informed policy makers and planners to lobby and advocate for resources needed for specific program interventions. To a great extent, they have also provided a good direction in designing appropriate national response to the problem of HIV/AIDS in Zambia.