Pregnancy in the rudimentary horn of a unicornuate uterus is uncommon and needs to be diagnosed at early stages to avoid uterine rupture to avert the high morbidity and mortality. In this case report, we discussed the advantage of three-dimensional transvaginal ultrasonography (3D TV-USG) in assessing the early pregnancy in the noncommunicating rudimentary horn of uterus. A 23-year-old woman approached us for routine pregnancy scan. The location of 5-week pregnancy was confirmed in the right noncommunicating horn of a unicornuate uterus by 3D TV-USG. She has undergone laparohysteroscopy, and excision of a gravid rudimentary horn was done. After an interval of 6 months, the patient received fertility treatment and conceived consequently. Although magnetic resonance imaging (MRI) is an excellent way of diagnosing uterine anomalies, the procedure is expensive, time-consuming, and not widely available. 3D USG is less expensive and more readily accessible for early diagnosis of uterine anomalies, particularly in health-care centers where MRI is not readily available or affordable.