Recent evidence suggests that yoga can be effective for reducing back pain. One recent randomised controlled trial (RCT) reported that yoga was cost-effective, from a societal perspective, for reducing back pain. Our study will be the first RCT to investigate the cost-effectiveness of yoga, from the perspective of the employer, for preventing and reducing back pain at work. Our study population will include 120 NHS staff members recruited from three hospital sites. Participants who meet the inclusion criteria will be randomised to receive either an eight-week yoga programme or an education programme consisting of evidence-based back care information. The yoga group will attend a weekly sixty minute yoga session and then practise at home using a back care DVD and an illustrated yoga booklet. Outcome measures will be collected at baseline, at eight weeks, and at six months. The Roland Morris Disability Questionnaire (RMDQ) will be the primary outcome measure for back pain. Sickness absence data, the EQ5D-5L and ICECAP-A will be used for the economic evaluation. Secondary outcome measures will assess back pain, wellbeing, quality of life, mood and resilience. The economic evaluation will be calculated using return-on-investment analysis (ROI) for the employer perspective and cost-effectiveness analysis (CEA) for the societal perspective. Qualitative data will be collected to determine the facilitators and barriers for successfully implementing a yoga programme at work.