Placental acretism is an adherencial pathology associated with a high maternal morbidity and mortality rates. Antepartum diagnosis is essential to plan a proper management and reduce serious complications. Risk factors in these patients include prior cesarean sections, uterine scars and placenta previa. Second level ultrasonography may detect placental acretism with high sensitivity and specificity; magnetic resonance imaging may play a complimentary role in the diagnosis of placental acretism when ultrasonographic findings are non-conclusive, specially when determining miometrium invasion in placental acretism (incretism, percretism). This paper reports the case of a patient treated at the ABC Medical Center of Santa Fe, in her second gestation with the diagnosis of an arcuate uterus, previous cesarean section and placenta previa who presented a vaginal bleeding during pregnancy; ultrasound evaluation, in the second trimester, identified a probable placental acretism, in the third trimester, the same technology suggested placenta percreta, complimentary magnetic resonance imaging supported this diagnosis, with probable invasion to bladder, bowel and abdominal wall muscles. Imaging studies were performed at the Hospital Angeles Lomas (Maternal Fetal Clinic). A diagnosis of placenta acreta-percreta, called for a multidisciplinary surgical team, availability of blood products and other resources to face probable complications associated to the obstetrical resolution. Maternal results were optimal since histopathological evaluation reported miometrial incretism, with placental invasion millimeters away from the uterine serosa. Most ultrasonographic studies evaluating the invasion degree of the placenta have small sample sizes, generating a greater degree of false positive or false negative observations. Therefore, we agree with other authors that in all acretism cases (independent of their invasion degree), a multidisciplinary surgical team should be assembled in order to increase patient's safety. Risk factor identification, precise prenatal diagnosis, and multidisciplinary management diminish maternal morbidity and mortality rates during obstetric resolution procedures.