The Lao Social Indicator Survey 2011-12 (LSIS 2011-12) is a nation-wide household-based survey of social development indicators. It combines the Multiple Indicator Cluster Survey (MICS) and Lao Reproductive Health Survey (LRHS) where the LRHS applied technical platform of Demographic and Health Survey (DHS). The LSIS is based on MICS4 platform and add-on DHS modules, for example, live birth history and the maternal mortality module. The LSIS 2011-12 was undertaken by the Ministry of Health and Ministry of Planning and Investment (Lao Statistics Bureau) in collaboration with other line ministries. UNICEF and UNFPA were the primary agencies giving financial and technical assistance to support the survey. In addition, USAID, AusAID, LuxGov, WHO, UNDP, SDC, JICA and WFP provided financial and technical input to the implementation of the LSIS. The main purposes of LSIS are to allow continued monitoring of progress towards the Millennium Development Goals (MDGs) and to serve as a baseline for the 7th National Socio-Economic Development Plan (7th NSEDP). The survey results can also be used by the Government and development partners to prepare policies, strategies and planning to improve the social environment of people in Lao PDR, especially women and men of reproductive age (15 to 49 years) and children age under five. In addition, the survey provides key sources and references for researchers and academics to conduct further analysis and research studies in specific areas using LSIS data.