Background- Objective: To evaluate the classification system based on Pyelocalyceal Distribution of Kidney stones and its role as an Outcome Predictor in Percutaneous Nephrolithotomy.Materials And Methods: This is a prospective observational study conducted on 144 patients of partial/total staghorn urolithiasis consenting for PCNL, for a period of 2 years at Institute of Nephro-urology, Bangalore. With regard to stone distribution in the pyelocaliceal system, the patients were classified as ‘‘no extra stone in middle calix’’ (NESMC) and ‘‘extra stone in middle calix’’ (ESMC). Results: In this study, 144 patients with urolithiasis were studied. The mean age was 44.53 years, with a predominance of males (93 patients, Mratio 1.82:1). Most stones were right-sided (57.6%) and single calculi were more common (57.6%). Radiopacity was found in 87.5% of cases, with non-staghorn calculi in 86.8%. Mid-calyx involvement was seen in 30.6% of patients, significantly associated with residual calculus (P = 0.010). Staghorn calculi were associated with a higher rate of residual calculus (57.9%, P = 0.007). There was no significant difference in residual calculus between single and multiple stones, or between right and left-sided stones. Conclusion: In conclusion, this study provides valuable insights into the factors influencing residual calculus following PCNL. By identifying significant predictors such as mid-calyx involvement and stone type, clinicians can better stratify patients for tailored treatment strategies, ultimately optimizing surgical outcomes and enhancing patient care in the management of urolithiasis.