Carpal tunnel syndrome (CTS) is a common disorder, for which various conservative treatment options are available. The objective of this study is to determine the efficacy of the various conservative treatment options for relieving the symptoms of CTS. Computer-aided searches of MEDLINE (1/1966 to 3/2000), EMBASE (1/1988 to 2/2000) and the Cochrane Controlled Trials Register (2000, issue 1) were conducted, together with reference checking. Included were randomised controlled trials evaluating the efficacy of conservative treatment options in a study population of CTS patients, with a full report published in English, German, French or Dutch. Two reviewers independently selected the studies. Fourteen randomised controlled trials were included in the review. Assessment of methodological quality and data-extraction was independently performed by two reviewers. A rating system, based on the number of studies and their methodological quality and findings, was used to determine the strength of the available evidence for the efficacy of the treatment. Diuretics, pyridoxine, non-steroidal anti-inflammatory drugs, yoga and laser-acupuncture seem to be ineffective in providing short-term symptom relief (varying levels of evidence) and steroid injections seem to be effective (limited evidence). There is conflicting evidence for the efficacy of ultrasound and oral steroids. For providing long-term relief from symptoms there is limited evidence that ultrasound is effective, and that splinting is less effective than surgery. In conclusion, there is still little known about the efficacy of most conservative treatment options for CTS. To establish stronger evidence more high quality trials are needed.