To compare the radiological peritoneal cancer index (PCI) score to the surgical PCI score for validating it as a non-invasive method to predict surgical outcomes. A descriptive study. Place and Duration of the Study: Department ofObstetrics and Gynaecology of the Aga Khan University Hospital, Karachi, Pakistan from September 2021 to May 2022. All successive patients diagnosed with advanced-stageovarian cancer were enrolled in the research. Prior to surgery, the severity of ovarian cancer was evaluated using the Sugarbaker Peritoneal Cancer Index score derived from radiological imaging. The score was compared to the surgical PCI score determined during the surgery. The correlation between the scores and residual tumour status was confirmed. The study included a total of 26 patients. The mean age of patients was 50.17 years, with a standard deviation of 11.04. Five (19.2%) patients underwent surgery first, whereas 21(80.8%) needed interval debulking surgery after receiving chemotherapy in the neoadjuvant setting. The interclass correlation value among radiological and surgical (PCI) was 0.52, with a 95% confidence interval ranging from 0.17 to 0.75. The Bland-Altman plot displays the agreement amongst the PCI scores, indicating a bias of 1.115 with a 95% confidence interval of 4.61. Surgical exploration revealed zero residual disease in 90% of persons with a PCI score <10. Patients with a PCI score <10 had significantly brief operative time and reduced blood loss compared to those with a score >10. Patients with a PCI score below 10 had also fewer complications. PCI is an efficient means for anticipating the success of surgery and the existence of residual disease without invasive measures. This can be very helpful in deciding the best time for surgery. Peritoneal cancer index, Advanced ovarian cancer, Carcinomatosis, Prognosis, Tumour load.