Sarcopenia can be defined as the age-related loss of muscle mass, strength and function. Although there is no specific level of lean body mass or muscle mass at which one can say sarcopenia is present, any loss of muscle mass is of importance because there is a strong relationship between muscle mass and strength. The introduction of new techniques such as proteomics will be necessary to understand the clinical and biochemical pathophysiology in the field of muscle aging. The concept of the proteome was first introduced in 1994 and is defined as Protein expressed by a giving genome. Two-dimensional electrophoresis (2DGE) is the first, important step in this proteomics strategy, followed by MALDI-ToF mass spectrometry. Using both technologies it is possible to be able to take a ‘snapshot’ of a cell so that many proteins can be separated, quantified and identified. We optimized 2D-gel electrophoresis to obtain high resolution 2D maps of 3 month and 30 month gastrocnemius muscle. The gels were stained, and the differentially expressed proteins were identified using 2D image analysis software. These proteins were then identified using peptide mass fingerprinting. The identified proteins were involved in energy metabolism, myofilament, cytoskeleton and detoxification.