We aimed to determine the change in levator hiatal (LH) dimensions using 3D high-frequency endovaginal ultrasound (EVUS) before and 1 year after treatment for pelvic organ prolapse (POP). Women with prolapse attending the urogynecology clinic between July and October 2009 were recruited. EVUS was performed using multifrequency (9-16 MHz) 360° rotational probe with a built-in 3D automatic acquisition system (Type 2052, ProFocus Ultra view, B-K Medical, Herlev, Denmark). The levator hiatal dimensions that were measured comprised anteroposterior (AP), left-to-right width, and area. Patients were followed up at 1 year, when EVUS was repeated. Eighty-nine women had symptomatic prolapse. Of these, 43 opted for surgery and 46 for nonsurgical treatment. Levator hiatal dimensions decreased in AP, width, and area at 12 months after surgery compared with baseline (p <0.05). However, there was no change in any of the dimensions after nonsurgical treatment. In contrast to conservative management, there is a significant decrease in levator hiatal dimensions 12 months following surgery for POP.