Urinary tract infections (UTI) are non-epidemic bacterial illnesses that are most frequent in infancy where 3 - 5% of girls and 1 - 2% of boys are affected at least once throughout their childhood. Among the factors that predispose them to a urinary tract infection, vesicoureteral reflux (VUR) is the most frequent by 25 - 50%, being present in 18 - 50% of the patients with their first episode of a urinary tract infection. However, for some authors, none had found major vesicoureteral reflux in any of their patients that justified immediate intervention. Actually, children with their first episode of a urinary tract infection are given exams such as a renal ultrasound and micturition urethrocystography (MUC) to evaluate the urinary tracts and to discard VUR. Controversy exists on the necessity of a MUC in every child, given that the majority of children present minor grades of VUR, in which a doctor handles, and only the major grades of VURs are considered other options of management