Longitudinal uterine septum is a common type of uterine abnormality and is categorized into incomplete and complete longitudinal uterus. Not all uterine septums can be detected by ultrasound because of certain imaging limitations that make it difficult to differentiate from other types of uterine malformations on the image. The initial diagnosis of uterine septum can usually be made by ultrasound, 3D ultrasound is a little more helpful in diagnosing uterine malformations, and in difficult cases, MRI is the gold standard in confirming the diagnosis of uterine malformations. Longitudinal uterine septum is now often removed by hysteroscopic surgery, which is minimally invasive and results in a quick recovery. Uterine malformations may be associated with miscarriage, preterm labor, fetal breech position, intrauterine growth restriction, abnormal progression of labor, and postpartum hemorrhage. Therefore, once detected, it is recommended to consult a doctor as early as possible and treat under the guidance of a specialized physician to avoid adverse outcomes.