Objective: The purpose of this literature review is to critically review the evidence for chiropractic as a treatment of primary insomnia. Methods: A search of the following databases up to October 2006 was conducted: PubMed, PEDro, MANTIS, CINAHL, and the specialized register of the Cochrane review group. We also performed hand searching of relevant journals. Randomized clinical trials, clinical trials, and case studies of chiropractic treatment of insomnia were included. It was required that each study used at least one form of standard patient outcome measure. Treatment strategies included manual therapy such as spinal manipulative therapy or muscle relaxation techniques. The review focused on articles published in indexed, peer-reviewed journals. Results: Fifteen studies met the selection criteria. There were no randomized clinical trials specific to chiropractic and insomnia. One study was a survey of opinion for treatment regimens for insomnia, which had low methodological scores. Another study assessed osteopathic cranial manipulation for insomnia, which appeared to have positive effects. Four studies identified physiotherapy treatment and manual therapy. A further 9 studies related to mind-body medical therapies and impaired health status, sleep disorders, and pain in the craniomandibular and cervical spinal regions. Conclusion: Some studies have noted improvement in insomnia following manual therapy; however, based on clinical trials, there is minimal evidence of support for chiropractic in insomnia. Further studies with high methodological scores need to be conducted.