Urinary tract infections (UTI) are common in childhood. Presence of pyuria and bacteriuria in an appropriately collected urine sample are diagnostic of UTI. The risk of UTI is increased with an underlying urological abnormality such as vesicoureteral reflux, constipation, and voiding dysfunction. Patients with acute pyelonephritis are at risk of renal scarring and subsequent complications such as hypertension, proteinuria with and without FSGS, pregnancy-related complications and even end-stage renal failure. The relevance and the sequence of the renal imaging following initial UTI, and the role of antimicrobial prophylaxis and surgical intervention are currently undergoing an intense debate. Prompt treatment of UTI and appropriate follow-up of those at increased risk of recurrence and/or renal scarring are important.