Presented at the 2015 Aquarius/SAC-D Science Team MeetingVariations in the Atlantic Meridional Overturning Circulation (AMOC) have global impact on the climate system, however until recently most AMOC observing programs have focused in the North Atlantic. Recent model and data analyses have suggested that critical water mass changes to the upper and lower limbs of the MOC occur in the South Atlantic, and only limited latitudinal coherence has been found to date between the MOC observations made by the North Atlantic observing systems at different latitudes. The USAMOC Science Team has given priority to the establishment of a MOC observing system in the South Atlantic. The International CLIVAR panel endorsed a South Atlantic MOC (SAMOC) Initiative to strengthen existing programs in the South Atlantic. SAMOC is an international cooperation between Argentina, Brazil, France, South Africa and the USA with collaborators from Germany, Russia, Spain, and the UK. The main objectives of the SAMOC program are to measure the strength and variability of the MOC as well as the meridional heat and fresh-water transport in the South Atlantic. This presentation summarizes the present status of the international SAMOC observing system and provides examples of recent observational and modeling results developed through coordination by the international SAMOC Initiative.