Abstract Percutaneous nephrolithotomy (PCNL) was applied in the prone position. But also, in recent years supine positions was applied in patients with kidney stones. Predicting how much renal stones can be cleared after surgery and possibility of complications is an important question for both surgeons and patients. Therefor different scoring systems are used to predict stone-free and complication rates before surgery. Patients and Methods: Between 2018 and 2920, 80 patients with renal stone who underwent PCNL in the supine position were evaluated preoperatively by S.T.O.N.E. and Guy’s scoring systems. The predictions of both scoring systems for stone-free and complication rates in patients who underwent PCNL in the supine position were evaluated. Also, these scoring systems were compared among themselves for reliability. Result: In both scoring systems, there was a statistically significant difference between postoperative stone-free (SF) and residual stone (RS) patients and in predicting the likelihood of complications in patients. No statistically significant difference was found between the two scoring systems in predicting the stone-free rate. Conclusion: Our findings revealed that S.T.O.N.E. nephrolithometri and Guy’s score systems can be used effectively to predict stone-free rate, complications and operation duration in supine position PCNL for renal stones.