Objective: The common cause of antenatal hydronephrosis in infants is temporary and permanent ureteropelvic junction stenosis (UPJS). Pyeloplasty is applied to all patients who have or have the potential to cause renal damage. This study, it was aimed to share the epidemiological data of our patients who underwent pyeloplasty.Materials and Methods: In our study, we evaluated 131 patients who were operated for UPJS between 2011 and 2021. The time of diagnosis, age of operation, duration of follow-up, gender, side of the pathology, complaints on admission, etiology of the pathology and contralateral kidney pathology were recorded. Results: 109 patients were included in the study. 76.1% of the patients were male and 23.9% were female. While pathology was more common on the left (65.1%) in boys, pathology was more common on the right (57.7%) in girls (p=0.036). The mean age of pyeloplasty was 39.27±48.01 months. The mean age of pyeloplasty in patients with antenatal diagnosis was 15.74±23.48 months, and the mean age of pyeloplasty in children with late diagnosis was 82.52±51.97 months (p=0.003). While 66.7% of UPD patients with aberrant vein pressure were diagnosed in the late period, 29.8% of the patients with intrinsic causes were diagnosed in the late period (p=0.005). Conclusion: Ureteropelvic junction stenosis is frequently diagnosed in the antenatal period and is common in boys and on the left. In our study, it was observed that right pyeloplasty was performed more frequently in girls. Patients with aberrant vascular pressure can also be diagnosed in the antenatal period. However, UPJS with aberrant vascular pressure is seen more frequently in patients admitted at older ages.