The authors prospectively evaluated the clinical event rate over a 72 hour period following femorocerebral angiography in 1002 procedures. The neurologic event rate was 1.3 per cent in the first 24 hours (0.1% permanent) and 1.8 per cent between 24 and 72 hours (0.3% permanent). The non-neurologic event rate (mostly hematomas) was 7.2 per cent. There were no deaths. One hundred and nine pieces of data per procedure were analysed statistically. Delayed cerebral ischemia does occur and could be secondary to the procedure. The low risk of judiciously performed cerebral angiography was confirmed. Carefully cataloguing all events for up to 72 hours neither verifies nor excludes angiography as the cause of deterioration.