Post-dural puncture headache (PDPHA) has been a vexing problem for patients undergoing dural puncture for spinal anaesthesia, as a complication of epidural anaesthesia, and after diagnostic lumbar puncture since Bier reported the first case in 1898. This Chapter discusses the pathophysiology of low-pressure headache resulting from leakage of cerebrospinal fluid (CSF) from the subarachnoid to the epidural spaces. Clinical and laboratory research over the last 30 years has shown that use of small-gauge needles, particularly of the pencil-point design, is associated with a lower risk of PDPHA than traditional cutting point needle tips (Quincke-point needles). A careful history can rule out other causes of headache. A positional component of headache is the sine qua non of PDPHA. In high-risk patients (e.g. age < 50 years, post-partum, large-gauge-needle puncture), patients should be offered early (within 24-48 h of dural puncture) epidural blood patch. The optimum volume of blood has been shown to be 12-20 ml for adult patients. Complications of autologous epidural blood patch are rare.