We report 5 cases of temporal arteritis associated with a diabetes whose good evolution under corticotherapy suggests a common pathogenesis. Several hypotheses can be formulated to explain the origin of the glycemic abnormality and to understand the way corticotherapy is effective. A moderate posology could at first have a hyperplasic effect on the insulin-secreting cells, and later on a favorable action on the vascular lesion and on an immunological disorder. Any definitive conclusion cannot be evolved yet. Only a more systematical study of the glycoregulation's abnormalities in the temporal arteritis will enable to answer the many remaining questions.