The Patagonian Icefield has the largest temperate ice mass in the southern hemisphere. Using remote sensing techniques, this study analyzed multi-decadal glacial retreat and expansion of glacier lakes in Northern Patagonia. Glacial boundaries and glacier lake boundaries for 1979, 1985, 2000, and 2013 were delineated from Chilean topographic maps and Landsat satellite images. Aster stereo images were used to measure mass balance from 2007 to 2012. The highest retreat was observed in San Quintin glacier. The area of glacier lakes increased from 13.49 km2 in 1979 to 65.06 km2 in 2013. Four new glacier lakes formed between 1979 and 2013. Between 2007 and 2012, significant glacial thinning was observed in major glaciers, including HPN1, Pared Norte, Strindberg, Acodado, Nef, San Quintin, Colonia, HPN4, and Benito glaciers. Generally, ablation zones lost more mass than accumulation zones.