All 187 neurosurgical biopsies which had been processed by the smear technique during the course of one year were reviewed. The method proved reliable, although in a few cases malignant tumors, eg, anaplastic astrocytoma and secondary carcinoma, could not be distinguished from each other, whether the specimen came from burr-hole biopsy or open operation (intracranial or spinal). Burr-hole biopsy combined with the smear technique proved safe, and many patients with inoperable malignant tumors or with nonsurgical conditions were spared a craniotomy—a considerable gain for the patient and for society. The smear technique also allows a rapid diagnosis of lesions exposed in the operating room, and this enables decisions about surgical strategy to be more firmly based.