Laparotomy is highly invasive and is associated with the risk of uterine rupture during pregnancy and necessitates cesarean delivery. Less invasive hysteroscopic operations are increasingly being performed in recent years. Intraoperatively, it is important to ensure that the residual septum measures < 1 cm; however, this is difficult to confirm during hysteroscopic procedures. Studies have reported that intraoperative hysterosalpingography is useful to evaluate the septum; however, this procedure is challenging and is associated with the risk of radiation exposure. We report a case of a septate uterus in a woman with a history of two miscarriages, who underwent hysteroscopic septoplasty under three-dimensional ultrasonographic guidance.