Congenital indifference to pain is often mistaken for congenital insensitivity. It is characterized by the occurrence since childhood of lesions, mainly cutaneous and osteoarticular secondary to strictly painless traumas. However, despite the lack of pain, the patient is able to discriminate a painful stimulus. Autopsy shows no abnormality of the nervous system. A dysfunction of the central endomorphinic systems has been suggested. Congenital analgesia is associated with anhidrosis in Swanson's syndrome (in which Lissauer the tractus is absent in the spinal cord) and with dysautonomia in Riley-Days's disease (in which there is a lack of amyelicinic fibres). On account of these data, some authors refuse the autonomy of congenital indifference and classify it in the group of the various autonomic and sensory neuropathies. However it seems justified to acknowledge the congenital analgesia with two varieties: congenital indifference in which there is no sensation of pain but normal sensory pathway and tonic function of endomorphinic system, congenital insensitivity in which the painful stimulus is not transmitted to the central nervous system.