This chapter presents results from an intensive glacier monitoring program, conducted over a period (2012-2014) on Universidad Glacier, the largest glacier in Chile outside Patagonia. It outlines the methods used to measure, calculate and interpret glacier mass and energy balance data, thereby serving as a guide for future field studies in the region. The chapter also presents the first complete mass balance estimates for Universidad Glacier and discusses meteorological controls on glacier ablation over two complete hydrological years. Glacier mass balance is the amount of mass gained or lost at a given point and time, usually expressed in millimeters or meters of water equivalent. The mass balance refers to the surface mass balance, i.e., mass changes resulting from the exchange of water and energy between the atmosphere and the glacier surface. Mass balance on mountain glaciers typically displays a strong relationship with altitude.