OBJECTIVES: The issue of low back pain (LBP) is as common as it is perplexing. LBP is thought to be a chronic issue in approximately 10% of the U.S. population. This condition has wide-reaching social and economical reverberations. Despite the availability of modern diagnostic tools, the cause of the pain generator is often unidentifiable. The authors were asked to create an overview of the etiology of LBP for physicians who implant neurostimulation devices for the treatment of chronic pain patients. Some prevalence data, based on the current available literature, have been provided for the more common structural conditions causing LBP. However, a comprehensive review of prevalence of various conditions and their respective manifestations as LBP is beyond the scope of this article. MATERIALS AND METHODS: A review was performed of frequently cited articles with search terms for "low back pain" using PubMed, Medline, and Google Scholar. The authors also reviewed other literature from commonly utilized sources in the field of interventional pain medicine such as the journals of Neuromodulation, Pain Medicine, Spine, and Neurosurgery in the publication date range of 1975 to the present. Moreover, recent edition textbooks of other specialties such as obstetrics and gynecology, neurology, internal medicine, and surgery were referenced to develop a comprehensive list of the differential diagnoses. In order to capture the broad scope of information presented in this article, the criteria used to choose the references included published peer-reviewed articles that provided information on LBP as a symptom of a case report to common presentations of various conditions as described in a number of current, and commonly used, textbooks in their specialty. RESULTS: The article serves as a reference for commonly cited causes of LBP as well as less common conditions presenting with LBP as a possible symptom, which may occur as a solitary pain generator or in combination with other etiologies. The information is structured in such a fashion to allow a comprehensive overview for every reader, including the most experienced implanting physicians. The article is designed to kindle critical thinking regarding the massive scope involved in the assessment of a patient with a complaint of LBP. The results of the comprehensive research to produce this article clearly indicate the broad scope of this list of differential diagnoses. The reader should be aware that the lists are by no means all-inclusive. Perhaps additional efforts will be necessary to build on the available information in this article in the future. Furthermore, although some prevalence data for LBP, as it is related to structural spine, is readily available based on the excellent work of our colleagues and presented throughout this paper, for other disease processes, the prevalence data are scarce to nonexistent. This underscores the need for further research to better understand this elusive condition. The size and breadth of the topic at hand in this article would arguably deserve its own comprehensive textbook. The complexity and discussion points of each identified pain generator could be given a chapter or section to reflect complex learning deserved by each topic. With these limitations, the authors recommend the reader to evaluate this article in the context of a broader topic of LBP and neurostimulation. CONCLUSIONS: LBP is an extremely common condition associated, as a symptom, with various disease processes, regardless of their relationship with the lumbar spine or its innervation. This article underscores the broad nature of LBP as a symptom of many diagnoses. The primary conclusion reached by the authors is the most important recommendation by all mentors in medicine, which is to obtain a comprehensive history and perform a complete physical examination on each patient. Despite the fact that there is an emerging school of thought questioning the validity of the physical examination, this tool continues to be the current standard of care and used by a majority of clinicians around the world. The physician must analyze the information obtained from his/her history, physical examination, and diagnostic tools with the recognition of the broad nature of the differential diagnoses of LBP in order to be able to best treat the patient.