This annual report describes the purpose and structure of the ARM Climate Research Facility and ARM Science programs and presents key accomplishments in 2006. Noteworthy scientific and infrastructure accomplishments in 2006 include: 1) Collaborating with the Australian Bureau of Meteorology to lead the Tropical Warm Pool-International Cloud Experiment, a major international field campaign held in Darwin, Australia; 2) Successfully deploying the ARM Mobile Facility in Niger, Africa; 3) Developing the new ARM Aerial Vehicles Program (AVP) to provide airborne measurements; 4) Publishing a new finding on the impacts of aerosols on surface energy budget in polar latitudes, and 5) Mitigating long-standing double-Intertropical Convergence Zone problem in climate models using ARM data and a new cumulus parameterization scheme.