This study models the economic costs of informal caring for people with back pain, using a microsimulation model, Care&WorkMOD, from 2015 to 2030. Care&WorkMOD was based on 3 national Australian Surveys of Disability, Ageing and Carers (2003, 2009, 2012) data sets for individuals aged 15 to 64 years. Estimated national income loss due to caring for people with back pain was AU$258 million in 2015, increasing to $398 million in 2030 (54% increase).