OBJECTIVE: Diuretic renal scintigraphy is important in diagnosing pelvi-ureteric junction obstruction (PUJO) in antenatally detected hydronephrotic (ANH) kidneys. Early-phase dynamic renal scintigraphy has several pitfalls contributing to the false interpretation of obstructed drainage, especially after pyeloplasty. This study explores the utility of delayed imaging in METHODS: Data from May 2019 to January 2024 was retrospectively studied to identify infants with ANH who underwent surgery for PUJO and pre-and post-surgical assessment of renal drainage using RESULTS: In a cohort of 104 patients with a mean age of 10.1 ± 6.5 months (range 2-36 months) at surgery, 106 renal units (bilateral involvement in two patients) were analyzed. There was no significant difference in the sum of obstructive and equivocal curve patterns (105 vs 79, p = 0.06) and T CONCLUSION: Delayed images in diuretic renal scintigraphy are crucial in accurately interpreting post-pyeloplasty drainage patterns and help overcome pitfalls of the dynamic study.