BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a rapidly progressive neurologic disorder characterized by an insidious onset of behavioral changes, dementia, cerebellar dysfunction, and movement disorders that rapidly progress to death. Iatrogenic transmission has been reported and associated with use of contaminated human growth hormone, dura mater and corneal grafts, depth electrodes, and in only four instances, with neurosurgical equipment. OBJECTIVE: Conduct an epidemiologic investigation surrounding a case of possible CJD transmission associated with neurosurgery. METHODS: Review medical and surgical records of the two CJD patients. Seek additional cases by matching death certificates and the New York State Department of Health dementia registry with list of patients undergoing neurosurgery. RESULTS: A 69-year-old man underwent a brain biopsy to rule out a presumed diagnosis of herpes encephalitis. Histological examination revealed spongiform degeneration of the cerebral cortex consistent with CJD. The following month, a 63-year-old man underwent a steriotactic-guided brain biopsy at the same hospital. Histologic examination revealed subacute necrosis of brain parenchyma with granulomatous vasculitis (no evidence of CJD). Approximately 6.5 years later, the patient was diagnosed with CJD. The only device known to have been used on both patients was a pneumatic drill, but different drill bits were used. The instruments used to open the dura were not described in the operative reports. Due to closure of the hospital, operating room logs, reprocessing records, and staff were not available for review or interview. None of the other subsequent neurosurgical patients is known to have died with a diagnosis of CJD. CONCLUSIONS: Transmission of CJD is extremely difficult, if not impossible, to prove on the basis of a single case. This investigation points out the difficulty of linking CJD patients, evaluating evidence of possible transmission, and preventing transmission. Current prevention and control strategies include screening organ and tissue donors for CJD prior to transplantation, identifying suspected CJD patients prior to high-risk surgery, and ensuring that potentially contaminated surgical instruments undergo the CJD-specific cleaning and sterilization processes recommended by the Centers for Disease Control and Prevention (CDC). Suspected nosocomial or iatrogenic transmission of CJD should be reported to state or local health departments and/or to the CDC.