It is estimated that pelvic organ prolapse (POP), the descent of organs into the vaginal cavity, affects approximately 3.3 million women annually in the United States. The onset of POP is due to the weakening or damage of pelvic organs and supportive ligaments and can be attributed to several factors with the most common being age, pregnancy, and weight gain. The uterosacral (USL) and cardinal (CL) ligaments, two major supportive pelvic ligaments, are typically used to surgically treat pelvic organ prolapse. Theses ligaments are either sutured to surrounding pelvic tissues or sutured to a synthetic transvaginal mesh to help support the prolapsed organ. Both of these procedures are marred with complications, with almost as many as 25% of women who have had a corrective surgery experiencing a reoccurrence of organ prolapse. This study focuses on the biomechanical properties of the USL and CL, in particular the creep behavior, a time-dependent mechanical phenomenon. Understanding the creep behavior is physiologically important since the ligaments are subjected to constant loads in-vivo. Our goal is to reveal the nonlinear viscoelastic creep behavior by performing planar biaxial tests on swine USL and CL. Specimens were split into three groups and were subjected to constant loads of 1N, 2N, or 3N for 20 min and allowed to recover for 200 min a total of three times. These loads were applied in the main in vivo loading direction and the direction perpendicular to the main in vivo loading direction. A 3D digital image correlation (DIC) system was used to perform non contact strain measurements. All specimens, regardless of the load, experienced the highest change in strain over time during the first creep test and mean isochronal curve data showed a nonlinear creep behavior. Such results are expected to greatly benefit future researchers by giving them the necessary input of the biomechanical properties of the native tissue to create better surgical techniques and mesh materials.