Unicornuate uterus with noncommunicating rudimentary horn occurs due to incomplete fusion of mullerian ducts. Pregnancy in this horn is a rare phenomenon usually resulting in rupture during second trimester of pregnancy. Prerupture diagnosis of pregnancy in rudimentary horn with ultrasonography is technically difficult, with sensitivity of 30%. We report a case of ruptured non-communicating rudimentary horn at 19 weeks in a woman with previous Cesarean delivery. She had a routine malformation scan in which diagnosis was missed. Later she presented to emergency in shock, with massive hemoperitoneum and ruptured horn. So a high index of suspicion is required to save this catastrophic event and associated maternal morbidity and mortality. In our opinion, routine excision of rudimentary horn should be undertaken during nonpregnant state laparoscopically. However, those women who refuse should be adequately counseled regarding potential complications and if pregnancy occurs in rudimentary horn, first trimester laparoscopic excision should be done.