Placenta increta during the first trimester of pregnancy is very rare. This report describes two cases of placenta increta that caused prolonged vaginal bleeding after a first-trimester abortion. We were encountered two cases of placenta increta in October 2012 and May 2013. Case I: A 35-year-old patient with continues vaginal bleeding from 2 months after curettage due to missed abortion in the first trimester. The uterus was large, the human chorionic gonadotropin (BHCG) level was 112 mUI/mL and ultrasound showed an echogenic mass in the lower segment of the uterine cavity. She was a candidate for curettage but received hysterectomy because of massive vaginal bleeding. Pathology reported placenta increta. Case II: A 32-year-old patient in the 12th week of gestation with missed abortion. After 6 weeks from curettage, she returned with continues vaginal bleeding, BHCG = 55 mUI/mL and sonography showing mixed echo lesion in the uterine cavity like hydatiform mole. Total abdominal hysterectomy was performed. Pathology reported placenta increta. In patients with a history of recent first-trimester abortion presenting with prolonged vaginal bleeding, uterine mass and low-level BHCG, a diagnosis of abnormal placentaion should be kept in mind.