The location of the receptive field for the tonic neck reflexes has been studied in a series of labyrinthectomized, decerebrate cats. Only the responses to rotation of the neck have been studied in the entire series. An inadequate number of observations on the response to tilting the head suggest that the conclusions are also applicable to this reflex. The response is retained unimpaired after section of all muscles connecting neck or trunk with the head, after bilateral section of muscular and cutaneous branches of the first three cervical nerves, and after resection and denervation of the muscles. On the other hand, the response is abolished ipsilaterally by unilateral circumcision of the first 3 cervical roots at their exit from the ligaments and abolished in all 4, extremities by bilateral circumcision, although muscular and cutaneous nerves are left intact . In some animals decerebrate rigidity is lost with the neck reflexes, in others it remains unimpaired. It is concluded that the reflex is ipsilateral and that the receptive field lies in the region of the upper joints of the neck, especially the atlanto-axial and atlanto-occipital joints.