Scintigraphy with the radiolabelled somatostatin analogue indium-111-DTPA-D-Phe-1-octreotide has recently been proposed for the imaging of CNS neoplasms expressing somatostatin receptors. While meningiomas are imaged with high sensitivity, neurinomas do not take up octreotide owing to the lack of somatostatin receptors. Neurofibromatosis is a relatively uncommon disorder in which meningiomas and neurinomas often occur in the same patient. Differential diagnosis between these two tumours by computed tomography and magnetic resonance imaging can be difficult. This study reports on 111In-octreotide scintigraphy in four patients with neurofibromatosis. 111In-octreotide scintigraphy was shown to be very helpful in the in vivo differential diagnosis: all four meningiomas showed intense tracer uptake, while all 15 neurinomas were negative (P < 0.001 by Fisher's exact test). It may be concluded that scintigraphy with 111In-octreotide is a useful diagnostic procedure in neurofibromatosis, complementing standard neuroradiological imaging procedures.