The effectiveness of relaxation techniques in the management of chronic pain was determined in this systematic review of published randomized controlled trials. Reports were sought by searching MEDLINE, psycLIT, CINAHL, EMBASE and the Oxford Pain Relief Database. Studies were included in this review if they were randomized controlled trials of relaxation techniques in chronic pain. Studies which investigated the effects of relaxation in combination with other interventions were not considered. Nine studies involving 414 patients met the predefined inclusion criteria and are critically appraised in this review. Meta-analysis was not possible, due to lack of quantitative data in the primary studies. Studies involved patients with a range of chronic pain conditions. The McGill Pain Questionnaire was the most common pain outcome used. Whilst four studies were able to show a significant difference for the pain outcomes in favour of relaxation for the pre- and post-treatment assessments, few statistically significant differences were reported in favour of relaxation when between treatment comparisons were used. Only three studies reported statistically significant differences in favour of relaxation (judged as a significant difference for at least 1 of the pain outcomes) compared to the other treatment groups. In rheumatoid arthritis the McGill Pain Questionnaire scores were significantly lower for patients receiving relaxation compared to those who were in the routine treatment control group. In ulcerative colitis significant differences were reported for six of seven different pain outcome measures in favour of progressive muscle relaxation compared to patients in the waiting list control group. In one of the two cancer pain studies, relaxation taught by nurses produced significantly lower pain sensation scores compared to the control group. Two studies reported significant differences in favour of the experimental control groups rather than for relaxation. There is insufficient evidence to confirm that relaxation can reduce chronic pain. Many of the studies both positive and negative suffer methodological inadequacies. Recommendations for future research into the effectiveness of relaxation techniques for chronic pain are made.