Nerve tissue protein S‐100 and neurone‐specific enolase levels in serum were studied in 10 patients before, during and for 2 days after elective carotid endarterectomy performed under general anaesthesia and using a Javid Shunt. In six patients, simultaneous cerebrospinal fluid samples were also obtained. Serum nerve tissue protein S‐100 was normal throughout the operation, but in one patient with severe hypertension, levels increased to 1.38 µg.l−1 at 1 h postoperatively. Two patients showed an increase in cerebrospinal fluid nerve tissue protein S‐100 during clamping: these patients also had neurological deficits at 6 months. Serum neurone‐specific enolase increased from 5.8 to 9.3 µg.l−1 during shunting while cerebrospinal fluid neurone‐specific enolase did not change. Uncomplicated carotid endarterectomy does not produce cerebral damage as measured by serum nerve tissue protein S‐100; cerebrospinal fluid nerve tissue protein S‐100 may be more sensitive for minor cerebral damage. Neurone‐specific enolase appeared to be nonspecific. The lack of correlation between the neuroproteins may need to be explained before relying on these simple assays as diagnostic indicators of cerebral ischaemia.