Objective: To conduct a systematic review and meta-analysis on the prognosis of acute idiopathic neck pain and disability. Data Sources: EMBASE, CINAHL, Medline, AMED, PEDro, and CENTRAL were searched from inception to July 2009, limited to human studies. Reference lists of relevant systematic reviews were searched by hand. Search terms included: neck pain, prognosis, inception, cohort, longitudinal, observational, or prospective study and randomized controlled trial. Study Selection: Eligible studies were longitudinal cohort studies and randomized controlled trials with a no treatment or minimal treatment arm that recruited an inception cohort of acute idiopathic neck pain and reported pain or disability outcomes. Eligibility was determined by 2 authors independently. Seven of 20,085 references were included. Data Extraction: Pain and disability data were extracted independently by 2 authors. Risk of bias was assessed independently by 2 authors. Data Synthesis: Statistical pooling showed a weighted mean pain score (0100) of 64 (95% confidence interval [CI], 6167) at onset and 35 (95% CI, 3238) at 6.5 weeks. At 12 months, neck pain severity remained high at 42 (95% CI, 3945). Disability reduced from a pooled weighted mean score (0100) at onset of 30 (95% CI, 2832) to 17 (95% CI, 1519) by 6.5 weeks, without further improvement at 12 months. Studies varied in length of follow-up, design, and sample size. Conclusions: This review provides Level I evidence that the prognosis of acute idiopathic neck pain is worse than currently recognized. This evidence can guide primary care clinicians when providing prognostic information to patients. Further research to identify prognostic factors and long-term outcomes from inception cohorts would be valuable.