OBJECTIVES: Multiple physical medicine modalities are commonly included as part of therapeutic interventions for mechanical neck disorders (neck pain). The objective of this review was to assess the effects of physical medicine modalities for pain in adults with mechanical neck disorders. SEARCH STRATEGY: We searched Medline, Embase, Chirolars, Index to Chiropractic Literature, Cinahl, Science Citation Index, Conference Proceedings Index, National Technical Information Services and reference lists of the retrieved articles from 1985 to December 1993 and we contacted content experts. SELECTION CRITERIA: Randomised trials and controlled trials of physical medicine modalities in adults with mechanical neck disorder. DATA COLLECTION AND ANALYSIS: Three reviewers independently assessed trial quality and two reviewers independently extracted data. Investigators were contacted to obtain information or data that could not be found in the published reports. MAIN RESULTS: Thirteen trials were included. The overall quality of the included trials was generally good. Two trials using electromagnetic therapy produced a significant reduction in pain (p <0.01) with three to four weeks of daily (eight hours per day) therapy sessions; and three using laser therapy did not differ significantly from a placebo (p=0.20) for six to 10 sessions of treatment. Not enough scientific testing exists to clearly determine the effectiveness of other therapies. This includes treatments such as exercise, traction, acupuncture, heat / cold applications, electrotherapies, cervical orthoses and chronic pain / cognitive behavioural rehabilitation strategies. REVIEWER'S CONCLUSIONS: There is little information available from trials to support the use of physical medicine modalities for mechanical neck pain. There is some support for the use of electromagnetic therapy and against the use of laser therapy with respect to pain reduction.