BACKGROUND: Chronic pelvic pain affects ∼15% of women, and is associated with significant societal cost and impact on women's health. Identifying factors involved in chronic pelvic pain is challenging due to its multifactorial nature and confounding between potential factors. For example, while some women with endometriosis have chronic pelvic pain, there may be comorbid conditions that are implicated in the chronic pelvic pain rather than the endometriosis itself. OBJECTIVE: We sought to explore multifactorial variables independently associated with the severity of chronic pelvic pain in women. STUDY DESIGN: We used baseline cross-sectional data from an ongoing prospective cohort, collected from patient online questionnaires, physical examination, and physician review of medical records. Participants were recruited from a tertiary referral center for endometriosis and chronic pelvic pain in Vancouver, British Columbia, Canada, from December 2013 through April 2015. Exclusion criteria included menopausal status or age >50 years. Primary outcome was self-reported severity of chronic pelvic pain in the last 3 months (0-10 numeric rating scale). Potential associated factors ranged from known pain conditions assessed by standard diagnostic criteria, validated psychological questionnaires, musculoskeletal physical exam findings, as well as pain-related, reproductive, medical/surgical, familial, demographic, and behavioral characteristics. Mann-Whitney, Kruskal-Wallis, or Spearman test were used to identify variables with an association with the primary outcome (P < .05), followed by multivariable linear regression to control for confounding and to identify independent associations with the primary outcome (P < .05). RESULTS: Overall, 656 women were included (87% consent rate), of whom 55% were diagnosed with endometriosis. The following factors were independently associated with higher severity of chronic pelvic pain: abdominal wall pain (P = .005), pelvic floor tenderness (P = .004), painful bladder syndrome (P = .019), higher score on Pain Catastrophizing Scale (P < .001), adult sexual assault (P = .043), higher body mass index (P = .023), current smoking (P = .049), and family history of chronic pain (P = .038). Severity of chronic pelvic pain was similar between women with and without endometriosis. CONCLUSION: Multifactorial variables independently associated with severity of chronic pelvic pain were identified, ranging from myofascial/musculoskeletal, urological, family history, and psycho-social factors. Continued research is required to validate these factors and to determine whether any are potentially modifiable for the management of chronic pelvic pain.