Objective: To determine if physiotherapy treatment applied to patients with levator ani muscle (LAM) avulsion identified after a vaginal delivery, reduces the LAM hiatus area. Material and Methods: A prospective observational study of 52 nulliparous (26 in the experimental and 26 in the control group). We included patients with LAM avulsion, diagnosed by 3-4D/transperineal ultrasound performed 3 months after delivery. Patients in the experimental group underwent a program of pelvic floor exercises, assisted by biofeedback and lumbopelvic stabilization exercises. Assessment of LAM was carried out at 6 and 9 months postpartum, using 3-4D/transperineal ultrasound, and taking the following measurements: levator hiatus area at rest, during Valsalva and at maximum contraction; LAM area, and thickness of right and left LAM. Results: Patients in the experimental group presented a reduction in the levator hiatus area at rest (17.0, 15.7, 15.9 cm 2 ), during Valsalva (23.0, 20.8, 19.9 cm 2 ) and at maximum contraction (15.6, 14.4 and 13.5 cm 2 ), in comparison with patients in the control group, who presented a levator hiatus area at rest of 17.4, 17.2 and 16.8 cm 2 , during Valsalva of 21.0, 20.8 and 20.3 cm 2 , and at maximum contraction of 16.6, 16.1 and 15.6 cm 2 , at 1, 6 and 9 months postpartum respectively (P < 0.05). However, no changes were appreciated in the successive examinations regarding LAM area between study groups: experimental 9.5, 8.9, 9.6 cm 2 versus 8.9, 9.0, 9.2 cm 2 in the control group. Conclusions: Physiotherapy treatment based on pelvic floor exercises with lumbopelvic stabilization exercises in patients with LAM avulsion reduces the levator hiatus area at rest, during Valsalva and at maximum contraction.