The work re-evaluates the meaning of stereotactic bioptic examination in 50 neurosurgical patients. Bioptic material gained for histologic purposes does not secure always the achievement of the correct histologic diagnosis. The authors critically reevaluate the possibilities of this diagnostic method. They do not consider as adequate to claim multiple expansive processes to be inoperable, respectively as being refractory towards therapy, when the histologic conclusion is lacking. In cases of inconsistency in histologic conclusions from two neuropathologists the further fate of the patient is conditioned by the neuropathologist's stand-point, but also by the clinical experience of the neurosurgeon who overtakes the final responsibility for the patient's further fate. Recently available methods (CT,MR, spectrography) are diagnostically not so precise as to be able to manage without stereotactic biopsy. (Tab. 3, Fig. 5, Ref. 10.).