A one year prospective study was undertaken to evaluate the usage of the cranial CT scan in private neurological practice. The impetus for the study emanated from a general impression that patterns of referral to neurologists were changing with regard to the nature of the patients' condition and that a large number of patients had already had a cranial CT scan before neurological consultation. A total of 826 cases were reviewed. Sixty (7%) had had a recent cranial CT scan before consultation, and 90% of these cases were referred by the patients' general practitioners. A provisional diagnosis was attempted by the GP in 36% of cases, and 50% of these were correct. Ninety-five per cent of the CT scans were normal. Eighty-three (10%) patients were referred for cranial CT scan after neurological consultation. The neurologists' reasons for CT scanning included investigation of epilepsy (20%) and exclusion of a structural cerebral hemisphere lesion (16%), acoustic neuroma (10%) and other posterior fossa lesions (16%). Ninety-one per cent of these CT scans were normal. In all, 143 (17%) patients underwent cranial CT scanning; of these almost half (42%) had been referred for the CT scan by the general practitioner before neurological consultation. This study contrasts the CT scan referring patterns of general practitioners with that of a neurologist and questions the possible overuse of this facility.