Objective: Urinary Tract Infection (UTI) is a common pediatrics infection that happens to 7% of total febrile pediatric especially in male infants less than 3 months and female less than 12 months of age. Approximately more than &% of girls and 2%of boys will have UTI by 6 years of age. One study from The American Academy of Pediatrics Ad Hoc Task Force on Circumcision report 11 fold increased UTI rate among uncircumcised boys compared to circumcised boys.  
Case: We reported a case of a 6 month old male baby with Urinary Tract Infection, the baby admitted to the hospital with high fever and phimosis. Patient were delivered by vacuum extraction for an indication of the threat of fetal stress with Apgar Score 8/9 and had history of hyperbilirubinemia when he was 5 days of age. There are no palpable abdominal mass. Through urinalysis we discovered elevated leukocyte (220-250/high pass field), positive leukocyte esterase and occult blood. We also did urine culture and find klebsiella oxytoca. 
Additional abdominal Ultrasonography was performed and discovered that the left kidney is larger than normal with changes on the kidney structure and dilatation of the ureter, showing the baby suffered from grade IV hydronephrosis and megaureter. The patient was then referred to tertiary hospital for further examination to evaluate the etiology of hydronephrosis, where Voiding Cystouregraphy (VCUG), renogram, CT scan and uretheral stent were performed.
Conclusion: This case has provent it is important to do through examination and additional screening especially ultrasonography in children with Urinary Tract Infection (especially recurrent UTI). At this case it is hard to determine whether the severity of the hydronephrosis already occurred prenatally or not.