Against this background, screening for VUR needs to be scrutinized and restricted to selected risk groups. What is known: • Screening of patients with ureteropelvic junction obstruction (UPJO) for vesicoureteral reflux (VUR) is recommended based on a small number of repeatedly cited studies. • The lack of conclusive evidence results in different treatment strategies and leads to difficulties when communicating diagnoses and treatment options to parents. What is new: • A robust prevalence for VUR in children with UPJO based on all published evidence and the resulting number needed to screen are given for decision-making in daily clinical practice. • The results may be a precursor for implementation into guidelines.