In the period March to May 1979, 6 patients with trigeminal neuralgia were operated on, neurovascular decompression being carried out in the posterior fossa. In 5 cases an arterial loop was found compressing the root of the V nerve at its apparent origin in the protuberance, and in one case a large calibrous twisted vein was found, compressing the root at its distal portion near the temporal bone. Of the 6 cases, 5 experienced immediate relief and one improved with the total disappearance of the pain after a month. In all the cases, the sensitivity of the face was preserved in all its various forms.