The article gives the retrospective analysis results of children’s patient cards with cases of acute pyelonephritis. The received data have been processed by a method of factorial analyses. In the general group of children, the significant risk factors are gastrointestinal disorders and peculiarities of the child’s constitution. The additional risk factors have been allocated for group of boys and girls. It was dysbacteriosis for girls. For boys it was artificial feeding, fimosis, constipations, dysbacteriosis, chronic tonsillitis and adenoiditis.
