Back pain is the leading cause for years lived with disability globally and among the main reasons for sickness absence (SA) and disability pension (DP). The objective of this study was to explore the occurrence of SA and DP and to estimate productivity losses among individuals with back pain compared with among matched population-based references. Explorative prospective cohort study using register microdata. A total of 23 176 people, aged 19-60 years, with a first visit to inpatient or specialised outpatient healthcare for back pain (International Statistical Classification of Diseases and Related Health Problems code M54) in 2010 in Sweden and a matched population-based reference group (n=115 880). Long-term SA (in SA spells >14 days) and DP and productivity losses, measured in € (2018 prices) by multiplying the SA and DP net days by the societal cost of each such day. In the back-pain group, 42% had SA or DP days; in the reference group, the corresponding proportion was 15%. Productivity loss per patient with back pain was €8928 during the 12-month follow-up period; in the reference group, it was €3499 (p<0.0001). SA and DP, leading to excess productivity losses among people with back pain, reflect the challenges these patients are facing to maintain their work capacity. Interventions to promote that individuals with back pain remain in paid work should be a priority in order to address the high costs. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.