BackgroundA substantial number of children experience spinal pain, that is, back and/or neck pain. Today, no ‘gold-standard’ treatment for spinal pain in children exists, but manipulative therapy is increasingly being used in spite of a lack of evidence of its effectiveness. This study investigates the effectiveness of adding manipulative therapy to other conservative care for spinal pain in a school-based cohort of Danish children aged 9–15 years.Methods and findingsThe design was a two-arm pragmatic randomised controlled trial, nested in a longitudinal open cohort study in Danish public schools. 238 children from 13 public schools were randomised individually from February 2012 to April 2014. A text message system and clinical examinations were used for data collection. Interventions included either (1) advice, exercises and soft-tissue treatment or (2) advice, exercises and soft-tissue treatment plus manipulative therapy. The primary outcome was number of recurrences of spinal pain. Secondary outcomes were duration of spinal pain, change in pain intensity and Global Perceived Effect.We found no significant difference between groups in the primary outcome (control group median 1 (IQR 1–3) and intervention group 2 (IQR 0–4), p=0.07). Children in the group receiving manipulative therapy reported a higher Global Perceived Effect: OR 2.22, (95% CI 1.19 to 4.15). No adverse events were reported. Main limitations are the potential discrepancy between parental and child reporting and that the study population may not be comparable to a normal care-seeking population.ConclusionsAdding manipulative therapy to other conservative care in school children with spinal pain did not result in fewer recurrent episodes. The choice of treatment—if any—for spinal pain in children therefore relies on personal preferences, and could include conservative care with and without manipulative therapy. Participants in this trial may differ from a normal care-seeking population.Trial registration numberNCT01504698; Results.