Low back pain is a very common condition, with about 80% of people suffering from it at some point in their lives. It is usually self-limited, resolving in 4 to 8 weeks in more than 50% of patients, yet the recurrence rate is high, about 85%. Because of the complexity of the bony, muscular ligamentous, and neural elements of the back, a specific anatomic diagnosis often cannot be made. Evaluation should include a careful history and physical examination, paying particular attention to alarm symptoms or "red flags" mentioned in the text. Imaging procedures are usually not necessary because of the lack of specificity and the high rate of early, spontaneous remission. Exceptions to this include history of recent trauma, presence of red flags or chronic unremitting course. Many treatment modalities, including physical therapy, ultrasound, thermal therapy, and local injection have been tried, but most studies are inconclusive as to their effectiveness. Prolonged bed rest is not indicated. Nonsteroidal anti-inflammation agents, judicious use of muscle relaxers, and patient education about the cause and prognosis are justified.