Spina bifida occulta occurs in 5-10% of the population, not all of whom display superficial signs. Attempted epidural puncture at the level of the lesion will almost certainly result in a dural tap. We report a patient who developed a postural headache after Caesarean section under epidural anaesthesia, in whom radiography of the spine later demonstrated spina bifida occulta. This problem has not been described previously, although it is unlikely to be an isolated case.