Purpose: The purpose of this study was to investigate magnetic resonance imaging (MRI) and 3-dimensional transperineal ultrasound (3D-TPUS) features of pelvic floor dysfunction (PFD) in symptomatic women in correlation with digital palpation and to define cut-offs for hiatal dimensions predictive of muscle dysfunction. Methods: This prospective study included 73 women with symptoms suggesting PFD. 3D-TPUS, MRI, and digital palpation of the levator ani muscle were performed in all patients. Levator hiatal antero-posterior (LHap) diameter and area (LH area) were measured at rest and at maximum muscle contraction. Results: The reduction in LHap diameter and LH area during contraction was significantly less in women with underactive pelvic floor muscle contraction (UpfmC) than in those who had normal pelvic floor muscle contraction by digital palpation (P<0.001). Statistically significant positive correlations (P<0.001) were found between the Modified Oxford Score and 3D-TPUS and MRI regarding the reduction in the LHap diameter (r=0.80 and r=0.82, respectively) and LH area (r=0.60 and r=0.70, respectively). A reduction in LHap of <6.5% on 3D-TPUS and <7.6% on MRI predicted UpfmC with sensitivities of 46.2% and 82.7%, respectively. A reduction in LH area of <3.4% on 3D-TPUS and <3.8% on MRI predicted UpfmC with sensitivities of 75.0% and 88.5%, respectively. MRI was more sensitive in detecting levator avulsion (63.4%) than 3D-TPUS (27.1%). Conclusion: MRI and 3D-TPUS had strong positive correlations with findings on palpation, and at certain cut-offs for hiatal dimensions, they can be used as complementary and objective tools to improve the accuracy of diagnosis and management planning of PFD.