Vaginal leiomyomas are rare benign solid tumours of the vagina. They can cause mechanical dystocia, which is a common problem in obstetrics leading to serious maternal and perinatal complications. Here we describe a patient with a vaginal leiomyoma diagnosed during the mid-trimester that could have caused dystocia. This 22-year-old woman presented with a vaginal mass and leaking vaginal fluid during pregnancy. On examination, a prolapsed, pedunculated mass, measuring 5 × 3 × 4 cm was detected in the anterior vaginal wall. Via a midline incision, the mass was easily enucleated and removed. Transvaginal surgical enucleation of the vaginal leiomyoma is usually curative and recommended as the initial treatment of choice to prevent for dystocia. Such treatment is indicated when the tumour is a potential obstacle to normal labour.