Combining RADARSAT images (1997) with either Landsat MSS (1987 for NPI) or TM (1986 for SPI), variations of major glaciers of the Northern Patagonia Icefield (NPI, 4200 km²) and of the Southern Patagonia Icefield (SPI, 13,000 km²) were studied. Of the five NPI glaciers studied, San Rafael Glacier showed a net advance, while other glaciers, San Quintin, Steffen, Colonia and Nef retreated during the same period. With additional data of JERS-1 images (1994), different patterns of variations for periods of 1986-94 and 1994-97 are recognized. Of the seven SPI glaciers studied, Pio XI Glacier, the largest in South America, showed a net advance, gaining a total area of 5.66 km2. Two RADARSAT images taken in January and April 1997 revealed a surge-like very rapid glacier advance. O’Higgins Glacier, which retreated more than 13 km during 1945-86, stagnated for 1986-97. Perito Moreno Glacier has the continuing stability. Other glaciers, Viedma, Upsala, Tyndall, and Ameghino, lost area, ranging from 0.52 to 7.16 km2. Between January and May 1997, Upsala Glacier lost an area of 2.71 km².

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