Patient is 18 years of age or older.

Patient has signed and received a copy of the Informed Consent form;

Patient has been implanted with a St. Jude Medical CE approved implantable neurostimulation system for the treatment of intractable chronic migraine:

* Patient diagnosed with chronic migraine (15 or more days per month with headache lasting at least 4 hours per day)

* Patient has failed three or more preventative drugs for treatment of their migraine

* Patient has at least moderate disability determined using a validated migraine disability instrument \[e.g., MIDAS \>11 or HIT-6 \>56\]

Peripheral Nerve Stimulation Registry for Intractable Migraine Headache