In the treatment of peptic gastroduodenal ulcers the modified vagomotor electrotest according to Burge has yielded remarkably good results as an intraoperative test for the completeness of proximal selective vagotomy (PSV). The test is as useful for the surgeon in training as for the expert in vagotomy. Moreover the clinical value of the test is demonstrated. If, according to this test, vagotomy is complete, an extreme reduction of gastric acid and a very low rate of relapsing ulcers are seen in our patients. We cannot recommend performing the PSV without this test.