The emergence of the neurosurgical patient as a novel clinical entity in the Netherlands was marked by a lingering conflict between neurologists and neurosurgeons, in which both types of specialists sought to assume the clinical and institutional leadership of neurosurgical patient care. In the 1920s and 1930s, neurologists had facilitated the establishment of the first generation of neurosurgeons in the country, and in the process, had managed to clinically and institutionally subordinate neurosurgery to neurology. As the demand for neurosurgical patient care grew, the neurosurgeons began to challenge this hegemonic relationship. The neurologists, however, were unwilling to give up their control, fearing that they would be bypassed in the diagnosis of patients eligible to neurosurgery. These conflicting aims and interests resulted in an intricate demarcation battle, in which the boundary work between neurologists and neurosurgeons was directly played out at the local workplace and at the meetings of the Study Club for Neuro-Surgery, and indirectly at various other sites of contestation, such as medical journals and academic lecture halls, as both parties sought to rally external stakeholders to their cause. During these negotiations, local, national, and international forces increasingly intertwined to shape the particular organization of Dutch neurosurgery in the middle of the twentieth century. By analyzing this multilayered demarcation process, this article draws attention to the complexity of medical boundary work, and to the way in which, despite pervasive international influences, specialist practice was ultimately negotiated at the local and national levels.