Glaciers are populated by a large number of microorganisms including bacteria, archaea and microeukaryotes. From an ecological point of view, three ecosystems can be differentiated in glaciers: the supraglacial ecosystem, the subglacial ecosystem and the englacial ecosystem. Several factors such as solar radiation, nutrient availability and water content greatly determine the diversity and abundance of microbial populations, the type of metabolism and the biogeochemical cycles. This huge diversity is threatened by climate change. This sampling place, Sarrios ice cave (Monte Perdido massif, Spanish Pyrenees) host one of the last permafrost deposits. Permafrost can provide us very worthy information about past climate and environmental conditions, therefore it should be studied as soon as possible due to the huge retreat that is already taking place. In order to study their metabolic potentials, samples of ice and permafrost were taken from an Antarctic glacier. The cells were harvested and their proteins were extracted and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI/TOF/TOF). Several proteins and enzymes were found that demonstrate the existence of cellular activity at subzero temperatures. In this way it is shown that the englacial microorganisms are not quiescent, but that they maintain an active metabolism and play an important role in the glacial microbial community.