The Patagonian icefields are the largest mid-latitude ice masses and yet few gla- ciological data exist for them. The presence of the Andes lying athwart the west- erlies makes for a dynamic glacial system with steep balance gradients and west- east equilibrium-line altitude gradients. The overall trend during the 20th century has been glacier retreat. However, whereas most eastern outlets retreated consis- tently from the beginning of the century, recession on the west began later, has been interrupted by readvances, and most recently has accelerated markedly, reaching higher mean rates of retreat than those on the east. This contrast may result from a predominantly precipitation-controlled mass-balance regime in the west and a dominant temperature control in the east. Superimposed on these contrasts is the anomalous behavior of certain calving glaciers, the oscillations of which contrast in magnitude, timing and sign with each other and with noncalving glaciers, and which in many cases do not relate directly to climate change. Two large calving outlets are at or near their Neoglacial maxima. The tantalizing frag- ments of information that exist suggest that there is a rich glaciological source to be mined in Patagonia yielding insights into glacioclimatic interactions, calving dynamics, Holocene climate change and the role of topography in controlling glacier behavior.