Neck pain occurs frequently in western societies. In the majority of cases, no specific cause can be identified. In order to gain insight into the clinical course and prognostic factors of non-specific neck pain, a systematic review was conducted. A computerized literature search was carried out to identify observational studies on non-specific neck pain and randomized clinical trials (RCTs) on conservative treatment of non-specific neck pain. Two reviewers scored independently, the methodological quality of all identified publications, using a standardized set of 13 criteria which were divided into five categories according to: study population, study design, follow-up, outcome measures and analysis/data presentation. To determine prognosis per study, an overall percentage of recovery for the most important outcome measures (pain, general improvement, functional status, health care utilization and lost days of work) was calculated. In total 23 eligible publications were identified (six observational studies and 17 RCTs). Only seven of 23 studies scored 50% or more of the 13 items, indicating a generally poor quality of methods. The most prevalent methodological shortcomings appeared to be selection of the study population, the sample size and analysis techniques. Most information regarding the clinical course is available for the group of patients with complaints for more than 6 months, who are treated in a secondary care or an occupational setting. In this group of patients, 46% (median) had less pain, with a range of 22-79% and a general improvement that ranged between 37 and 95% (47% median). The reduction in the use of analgesics ranged between 32 and 80% (37% median). Six studies reported on prognostic factors. Bearing in mind the limited number of studies and the low methodological quality, there are some indications that the localization (radiation to the arms/neurologic signs) and radiologic findings (degenerative changes in the discs and joints) are not associated with a worse prognosis. A higher severity of pain and a history of previous attacks however, seems to be associated with a worse prognosis.