Perineal laceration commonly occurs due to dilation of the birth canal at the time of foaling in primiparous mares. A 7-year-old Thoroughbred mare was presented with faecal contamination of the external genitalia. She was having history of constant straining three days after the mare`s first foaling. Physical examination revealed the tearing extended from the deep part of vagina through muscles of the perineal body involved rectal floor and anal sphincter. Tentative diagnosed was third-degree perineal laceration therefore one-stage surgical procedure and a modified surgical procedure at three-week intervals was performed. During postoperative care for 3 weeks, soft faces was a key factor in success. After 3 weeks, the patient was recovered to normal condition completely.