Incarceration and sacculation of a retroflexed gravid uterus is relatively benign, in contrast with pregnancy in a rudimentary uterine horn which can lead to perforation and hemorrhage. We report a case of pregnancy in an incarcerated sacculated non‐communicating rudimentary horn mimicking incarceration with sacculation of a retroflexed gravid uterus. Both physical and sonographic findings were unhelpful in the differential diagnosis. Therefore, decision for laparotomy in such cases should be based on severity of symptoms.