Neuropathic pain is defined as pain initiated or caused by a primary lesion or dysfunction in the nervous system. It is a devastating and difficult to manage consequence of peripheral nerve injury and has a variety of clinical symptoms. Neuropathic pain is a major health problem. It has been estimated that 70% of patients with advanced cancer and inflammatory pathologies are afflicted by chronic pain. About 95% of patients with spinal cord injuries have neuropathic pain problems. Chronic pain is debilitating and cause of depression and decreasing quality of life. Pharmacological treatment for the symptoms of painful neuropathy is difficult, because there has been limited understanding of the underlying causes and systemic levels that an effective dose can have on multiple side effects. The use of molecular methods, such as gene therapy, stem cell therapy and viral vector for delivery of biologic antinociceptive molecules, has led to a better understanding of the underlying mechanisms of the induction of intractable neuropathic pain.