Abstract An overall retreat of glaciers has been observed in the Andes of central Chile during the last ~100 years. Precipitation is mainly of frontal origin and concen¬trates in winter months. Analysis of precipitation data shows a decrease until 1976, anincrease thereafter north of 34ºS and a decrease south of 34ºS, but overall no significant trends during the last quarter of the 20th century. Analysis of radiosonde data of central Chile shows mid-tropospheric warming with an elevation increase of the 0ºC isotherm of 122 ± 8 m and 200 ± 6 m in winter and summer, respectively,during the 27-year period between 1975 and 2001. The results point to a snowlineelevation increase in the region during the last quarter of the 20th century and a concurrent rise of the equilibrium line altitude (ELA) and suggest that mid-troposphere warming is the main cause for glacier retreat in central Chile.