Abstract Background In spite of Percutaneous nephrolithotomy (PCNL) became the first-line treatment option for patients with large and complex renal stones, there still remains a need of using open stone surgery (OSS) for removal of stones as a second or third line of treatment option. To date, 3 scoring systems have been proposed utilizing different metrics including the Guy’s Stone Score, S.T.O.N.E. nephrolithometry and the Clinical Research Office of the Endourological Society (CROES) nomogram, and that used to assess and estimate the treatment success rate. Aim of the Work To evaluate and compare between OSS and PCNL in the management of renal stones by using the S.T.O.N.E. nephrolithometry scoring system to predict and assess the stone free rate and the correlation with peri-operative complications in that two procedures. Patients and Methods A total 100 patients who need surgical intervention for renal stones were treated with OSS (35 pa ents) and PCNL (65 pa ents) from January 2019 ll the end of October 2019, were invited to participate in the present study. This was a multicenter, comparative, prospective cohort controlled study. This study was controlled by the standard results recorded in the previous literatures. Only adult(>18 ys. Old) patients with renal stone size ≥ 20mm were involved in the study. Peri-operative and follow-up data included stone free rate and complications were collected for all patients and were compared between both procedures. S.T.O.N.E nephrolithometry scoring systems was applied to preoperative non-contrast computed tomography(CTUT) for all cases and compared the results of both procedures. Stone-free rate was diagnosed using early postoperative kidney, ureter, bladder X-rays(KUB) and another CTUT on the postoperative day30. Results There was a significant difference between the PCNL group and the OSS group in the primary stone free rate (90% and 97.5% respec vely, p-value=0.021), peri-operative major complications (3% and 14.3% respectively, p-value=0.033), opera ve me (123.46 ± 34.61 and 175.71 ± 55.10 respec vely, p-value=0.000) and postopera ve hospital stay (3.52 ± 0.84 and 5.23 ± 1.00 respec vely, p-value=0.000), while there was no significant difference in the intra-opera ve bleeding requiring blood transfusion (10.8% and 14.3% respec vely, pvalue=0.124). S.T.O.N.E score showed a significant difference between PCNL and OSS groups ( 7 (6-11) and 10 (7-12) respectively, p-value=0.000) and it also had a significant rela on with the outcome SFR (p-value=0.000) a er both PCNL and OSS(r= -0.581 and r= -0.567 respec vely), the higher the score, the lower the SFR and the higher the possibility of OSS choice. While this score had on relation with the peri-operative complications. Conclusion The S.T.O.N.E. nephrolithometry score was predictive of the stone-free status in both surgical procedures (PCNL and OSS) and can be used as an formal guidance for surgical planning and patient counseling. This score would be classified into two categories “low” score range from 5 to 8 recommend PCNL procedure with expec ng SFR of 88% to 97% and “high” score range from 9 to 12 recommend Open Stone Surgery with expec ng SFR of 90% to 96%, to reach the most acceptable results for each procedures to sa sfy the patient and the doctor. The S.T.O.N.E score was not associated with the peri-operative complications in both procedures.