Neurogenic muscular atrophy (NMA) is the most frequent diagnosis obtained from reading a muscle biopsy. It is characterized by specific histological changes which distinguish NMA from other important muscle pathologies including the primary myopathies such as the muscular dystrophies as well as the inflammatory muscle disorders. Within the group of denervation atrophies, NMAs due to motor neuron diseases are associated with particular histological patterns. The diagnosis of NMA in muscle biopsies requires special methods, mainly enzyme and immunohistochemistry, but also resin histology and in some cases electron microscopy. Analysis of a combined muscle and sural nerve biopsy provides the opportunity to compare the extent of degeneration in the motor and sensory systems, respectively. Muscle fiber typing by enzyme and immunohistochemistry also leads to the detection of selective type 1 and type 2 muscle fiber atrophies which are relevant in the differential diagnosis of neuromuscular diseases.