High-tone pelvic floor dysfunction (HTPFD) is a neuromuscular disorder of the pelvic floor characterized by non-relaxing pelvic floor muscles, resulting in voiding and defecatory symptoms, sexual dysfunction, and pelvic pain. A challenge in the management of HTPFD has been a lack of quantitative measures of pelvic floor muscle physiology for accurate diagnosis. Near infrared spectroscopy (NIRS) is a non-invasive diagnostic tool for real time measurement of physiologic muscle parameters. A vaginal probe incorporating a multipoint NIRS emitter/detector array was linked wirelessly to a four-wavelength continuous wave NIRS instrument. Concentration changes in O2Hb and HHb were recorded, and the difference between the two (HbDiff) was calculated for the right and left pelvic floor musculature over the course of five maximum voluntary contractions (MVCs) and one sustained maximum voluntary contraction (SMVC) of the PFM. Half-recovery time of hemoglobin difference, HbDiff(½RT), following sustained maximal voluntary contraction (SMVC), was calculated. It is a validated, NIRS-derived, oxygen kinetic parameter indicating muscle metabolic function. The aim was to evaluate if differences in HbDiff(½RT) could be detected in women with HTPFD compared to controls. Serial measures were recorded for 24 asymptomatic control and 5 women with HTPFD. In women with HTPFD there was an absence of desaturation as well as a failure to recover to pre-contraction oxygenation even after relaxation. Throughout the pelvic floor HbDiff(½RT) was prolonged in the HTPFD subjects, indicating worsened pelvic floor metabolic function. This confirmed that assessment of pelvic floor muscle dysfunction using NIRS monitoring is feasible for the detection of HTPFD.