The objective of this study was to examine which factors during pregnancy and postpartum predict pelvic girdle pain (PGP) at 12 weeks postpartum among working women. A total of 548 Dutch pregnant employees were recruited in 15 companies, mainly health care, child care, and supermarkets. The definition of PGP was any pain felt in the pelvic girdle region at 12 weeks postpartum. Participants received questionnaires at 30 weeks of pregnancy and at 6 and 12 weeks postpartum with demographic, work-related, pregnancy-related, fatigue, psychosocial, PGP-related and delivery-related questions. Univariate and multiple logistic regression analyses were performed. Almost half of the women experienced pain in their pelvic girdle at 12 weeks postpartum. However, the level of pain and the degree of disability due to postpartum PGP was low. Pregnancy-related predictors for PGP at 12 weeks were history of low back pain, higher somatisation, more than 8 hours of sleep or rest per day, and uncomfortable postures at work. The pregnancy and postpartum-related predictors were: more disability at 6 weeks, having PGP at 6 weeks, higher mean pain at 6 weeks, higher somatisation during pregnancy and at 6 weeks postpartum, higher birth weight of the baby, uncomfortable postures at work and number of days of bed rest. Based on these results, it is concluded that extra attention should be given to women who experience PGP during pregnancy to prevent serious PGP during late pregnancy and postpartum. More research is needed to confirm the roles of hours of sleep, somatisation, and bed rest in relation to PGP.