Megaureter is a descriptive term denoting dilated ureter. It is defined as any retrovesical diameter of the ureter equal to or greater than 7 millimeters, from the 30th week of pregnancy onwards. Classification is based on the cause and presence of obstruction or reflux. There are four categories of megaureters: reflux, obstructive, obstructive with reflux, and non-reflux / non-obstructive, and each of them can be primary or secondary, depending on the cause. Megaureter occurs more often in boys and is more commonly located on the left side. The primary megaureter is the second most common cause of hydronephrosis. Megaureter is usually detected prenatally as a random finding. Children are usually asymptomatic, and if symptoms exist, the patients usually present with recurrent urinary tract infections, abdominal pain, unexplained fever etc. The diagnosis is usually confirmed by ultrasound. Today there is a newer ultrasound method called ceVUS, which is similar to MCUG, but it does not use ionizing radiation. If further diagnosis is needed, then dynamic renal scintigraphy, MRU and fMRU are also performed. Initial treatment of all types of megaureters is conservative. Indications for surgical treatment are massive ureterohydronephrosis , progressive loss of renal function, and unsuccessful conservative treatment. There are numerous methods of surgical treatment. In children older than one year, ureteral reimplantation is the method of choice. Initially, it was done with an open approach that was technically difficult to perform. Over time, less invasive methods were developed with better postoperative outcomes and a reduced complication rate. These methods include laparoscopic reimplantation of the ureter by transvesical approach and endoscopic balloon dilatation. Temporary surgical methods include double J-stent insertion, reflux reimplantation, and ureterostomy placement.