The muscular dystrophies are a group of clinically and genetically heterogeneous myopathic disorders characterized by progressive degenerative change in skeletal muscle fibres. Several proteins from sarcolemma (dystrophin, sarcoglicans, caveolin-3), and muscle fibres cytoplasm (calpain 3) have been identified. Most of these proteins appear to play a role in supporting the structure of muscle fibres and some of them are known to be involved in molecular signalling and biochemical processes. Mutations in their genes are responsible for different forms of muscular dystrophies such as: i) Duchenne Muscular Dystrophy (DMD), Becker Muscular Dystrophy (BMD) which are X-linked allelic myopathies caused by dystrophin deficiency; ii) Limb Girdle Muscular Dystrophy type 2A (LGMD 2A) caused by mutations in the calpain 3 gene. Immunofluorescence and immunoblotting (western blotting) are the two methods used in our studies in order to evaluate the modifications of protein expression as a diagnostic tool. Dystrophin expression detected by immunofluorescence at the sarcolemma of normal skeletal muscle fibres is absent or severely reduced in DMD. Complete lack of this protein revealed by Western blot analyses confirms DMD diagnosis. In contrast, to BMD patients we can observe a reduced staining at the sarcolemma level and by Western blot we can observe a dystrophin of abnormal size or abundance. Concerning the study of calpain 3 protein, responsible for LGMD 2A, the only sensitive method capable to detect the expression's changes is Western blotting.