Background: The placenta accreta spectrum (PAS) is a spectrum of placental attachments, with an incidence ranging from 1/533 to 1/731 deliveries and a maternal death rate reaching 7%. Moreover, repeated CS is considered the most significant risk factor. Objective: the present study, we aimed to validate the Cali et al. scoring system for predicting the PAS. Methodology: A prospective observational study that was conducted at The Ultrasound Unit and Maternity Hospital in The Obstetrics and Gynecology Department, Zagazig University through the period from January 2020 to May 2023 where fifty-seven patients were included. Every patient was subjected to a Cali ultrasonographic scoring system to predict placental invasion and to the FIGO clinical grading system during delivery. Furthermore, histopathological examination was performed for patients who underwent hysterectomy. Results: PAS 3 could predict the presence of placenta percreta with an area under the curve of 0.625, a sensitivity of 75%, a specificity of 50%, a positive predictive value of 60%, a negative predictive value of 66.7%, and an overall accuracy of 62.5% (p=0.487). Conclusion: After validation of the Cali et al. scoring system in our study, the prediction of placental invasion was lower than that reported by Cali et al. in their research. Moreover, the performance of the Cali et al. scoring system was not better than that of other scoring systems in the prediction of placental invasion in PAS patients.