This study is a prospective, consecutive, 3-year cohort study of women with back pain in an index pregnancy. The aim was to describe the physical status and disability among women with back pain 3 years after delivery. Pain was identified as lumbar back pain, posterior pelvic pain or combined lumbar as well as posterior pelvic pain. Previous studies have established that all three types of pain can be reduced by structured physiotherapy during pregnancy, and the beneficial effect may last for several years. Though it is known that some women have residual pain for a long time, the relative incidence of the three pain types and their degree of disability associated with each have never been reported. Neither has any study presented findings of a physical examination of women 3 years post partum with a focus on the type of pain. All women who were registered as having experienced back pain during an index pregnancy were interviewed by mail 3 years post partum. Women who had residual back pain filled in an additional questionnaire and were physically examined. Out of 799 pregnant women, 231 had some type of back pain during the index pregnancy, and 41 women had pain 3 years later. Women with combined lumbar and posterior pelvic pain were significantly more disabled (P<0.05) and had significantly lower endurance in the lumbar back and hip abduction muscles (P<0.01). Some 5% of all pregnant women, or 20% of all women with back pain during pregnancy, had pain 3 years later. The key problem may be poor muscle function in the back and pelvis.