Background: OASIS injuries are a relatively common complication of vaginal deliveries; however, buttonhole tears are less common. A literature review identified no cases of buttonhole tears greater than 3 centimetres. Case: A 33-year-old primigravida woman underwent an induction of labour for decreased fetal movements and had a NVD of a 3.7 kg at 39 6/7 gestation infant with examination revealing a posterior vaginal wall tear. On routine per rectal exam post-suturing, a full thickness tear through rectovaginal fascia was identified Further assessment in theatre confirmed an extensive 10 cm full thickness rectal buttonhole tear with a completely intact sphincter complex, repaired with colorectal assistance. At review in the multidisciplinary clinic 6 months post-operatively, she reported good continence of faeces and flatus. Discussion: A literature review identified very few similar cases of isolated buttonhole tears with no anal sphincter involvement. This may be due to its rarity but also possibly due to under-reporting. No cases documenting a tear beyond 3 centimetres was identified, making this an unusual occurrence. Rectal buttonhole tears are a rare but potentially serious complication of labour with increased risk of a chronic rectovaginal fistula, incontinence and significant psychological morbidity. This case highlights the importance of routine PR examinations, early diagnosis and a MDT approach in order to achieve good outcomes A thorough, systematic examination of the perineum, rectum and vagina should be performed after all vaginal deliveries to ensure prompt recognition and management and in doing so mitigate the potentially serious medicolegal implications of a missed injury.