Background:Pelvic-ureteric junction obstruction (PUJO) is considered the most common pathology for hydronephrosis in neonates. Full recovery of kidney impairment due to PUJO is possible, especially when pyeloplasty is indicated as surgery is mostly conducted when deterioration is identified, early detection should be considered to prevent further complications. Commonly used kidney damage biomarkers are not sensitive enough to predict kidney damage. Neutrophil gelatinase-associated lipocalin (NGAL) and urinary interleukin 18 (IL-18) are markers of early kidney damage with different characteristics. This study aimed to evaluate the relationship between these two markers with the degree of histopathological kidney damage in Wistar rats induced by PUJO.Methods:A total of thirty male Wistar rats, 200–250 g, were divided into three groups: (1) control, (2) sham, (3) PUJO (4th, 7th, 14th, and 21st days). Urine NGAL, IL-18 levels, and renal histopathology were observed on day 0, 4, 7, 14, and 21. Statistical analysis was performed using the Kruskal–Wallis and Mann–Whitney test withPless than 0.05 considered significant.Results:There was no significant difference in urine NGAL levels between groups, while IL-18 levels were significantly different based on the Kruskal–Wallis test (P0.031). The results of the Mann–Whitney test showed a significant difference in IL-18 levels between the control group and the PUJO group on day 4 (P=0.028); the Sham surgery group with the PUJO group on day 4 (P=0.014); the PUJO group on day 4 with the PUJO group on the 7th day (P=0.008); and the PUJO group on the 7th day with the PUJO group on the 14th day (P=0.033).Conclusion:Urinary IL-18 levels can be used as a predictor of kidney damage in acute-subacute PUJO cases.