The incidence of Obstetric anal sphincter injury among Nepalese women with vaginal birth over a 2-year period was 0.33%, which was lower than other South Asian studies. Grade III Obstetric anal sphincter injury was the frequent most type. The injuries were more common in women with Janajati ethnicity, primipara and women who did not have episiotomy. Problems with flatus holding and urine holding were present in almost one-fourth of the women with Obstetric anal sphincter injury at follow up.