To help determine neurosurgical needs within communities and within the nation, operations and diagnostic procedures performed by neurosurgeons on residents of Olmsted County, Minnesota, in the 5 years of 1970 through 1974, were tabulated. This county was studied because its medical records are virtually complete. Annual rates (per 100,000 population) were 42 for lumbar disc removal, six for cervical disc removal, and seven for brain-tumor therapy. Other less frequent occasions for neurological surgery are also tabulated.