The authors review the literautre and then proceed to analyse a series of 16 cases of Gougerot Sjögren Syndrome. The electromyogram (EMG) was abnormal on only 2 occasions. Histologically inflammatory aspects could be seen on 4 occasions with perifascicular atrophy in one case. Atrophy of II fibres was present in 7 cases together with signs of disorganization of the mitochondrial reticulum and images of mitochondrial aggregates. Under the electron microscope minor anomalies were particularly visiole and the internal structure was normal as often as not. Overall it is possible to distinguish forms of a subacute polymyositis type (4 cases), and a pauci-inflammatory myalgic type proximal to the scappular predominance (4 cases), in which the mitochondrial anomalies are commonest. Another "infraclinical" group shows no other frankly pathological changes. Finally in 3 cases the "dry" syndrome is strictly free of any muscular attack.