The introduction of molecular genetics in medicine, specifically in the field of neuromuscular pathology, has created a drastic change in the diagnostic approach used for neuromuscular disorders. Diagnosis of muscle biopsy is based on important aspects such as morphology and histochemistry, but nowadays immunohistochemistry and Western blot analysis of certain proteins is of utmost importance for a correct diagnosis in a large number of neuromuscular disorders and is crucial to direct the genetic study, which is also necessary. To date, more than 30 muscular dystrophy types have been genetically characterized, and the protein product is known in most of them as well as its structural location in the muscle fiber and its relation with other muscle proteins and the extracellular matrix. With the diagnostic specificity conferred by the absence of expression by a specific protein or a mutation of a specific gene, we have learned that similar clinical phenotype may occur in different diseases, such as Duchenne muscular dystrophy and gamma-sarcoglycanopathy, but also that mutations in the same gene may cause different clinical phenotypes, as occurs in Miyoshi distal myopathy and limb girdle muscular dystrophy 2B, both caused by mutations in the dysferlin gene. Herein we describe the recommendable diagnostic methodology and strategy to be employed in the study of the large group of the <<limb girdle muscular dystrophies >>, especially focused on the autosomal recessive dystrophies, taking the study of dystrophinopathies as an example.