The prevalence of kidney scarring after UTI is approximately 5-57%. UTIs are caused mainly by bacteria that cause local and systemic immunological reaction that are accompanied by cytokines. These cytokines are a main factor in the inflammatory process. They are produced by leukocytes, macrophages, fibroblasts, endothelial cells and epithelial cells in the kidney tissue. Interleukin 6 and 8 (IL-6 IL-8) were found in high levels in the urine of children and adults who suffer from UTIs. Other studies on animals have found a relationship between inflammatory reaction and scarring in the kidney. We hypothesize that we will find a similar relationship between the level of IL-6, IL-8 in the urine during acute pyelonephritis in children and the probability of kidney scarring.