Placenta accreta is a rare and potentially life-threatening complication of pregnancy characterized by abnormal adherence of the placenta to the uterine wall. A previously scarred uterus or an abnormal site of placentation in the lower segment is a major risk factor. The aim of this study was to investigate the change in the incidence of placenta accreta and associated risk factors along four decades, from the 1970s to 2000s, in a tertiary south Italian center. We analyzed all cases of placenta accreta in a sample triennium for each decade. The incidence increased from 0.12% during the 1970s, to 0.31% during the 2000s. During the same period, cesarean section rates increased from 17 to 64%. Prior cesarean section was the only risk factor showing a significant concomitant rise. Our results reinforce cesarean section as the most significant predisposing condition for placenta accreta.