Three cases of nemaline myopathy are reported. The first one was characterized by delayed motor milestones, hypotonia and proximal weakness in a 2-year-old girld. The second case was diagnosed at 19 in a boy who suffered from a severe scoliosis without any neurological sign. The third patient was a 31 year-old man who had a progressive muscular weakness of limb girdles. Muscle biopsy revealed rods in muscle fibers with Gomori trichrome staining in two cases, and by electron microscopy in one case only. Variations of fiber calibration, fiber I predominance and a myofibrillar disorganization were seen in two cases. Clinical, histopathological and physiopathological of nemaline myopathy are discussed.