Peripheral nerve blocks have long been used in headache treatment. The most widely used procedure for this purpose has been greater occipital nerve (GON) block. The rationale for using GON block in headache treatment comes from evidence for convergence of sensory input to trigeminal nucleus caudalis neurons from both cervical and trigeminal fibers. Although there is no standardized procedure for GON blockade, the nerve is usually infiltrated with a local anesthetic (lidocaine, bupivacaine, or both). A corticosteroid is sometimes added. Several studies suggested efficacy of GON block in the treatment of migraine, cluster headache, and chronic daily headache. However, few were controlled and blinded. Despite a favorable clinical experience, little evidence exists for the efficacy of GON block in migraine treatment. Controlled studies are needed to better assess the role of GON block in the treatment of migraine and other headaches.