THE MAJORITY of the concern in pediatric urology is centered around infections and anomalies, the former occupying the greater portion of the practicing pediatrician's problem in this field. Therefore, discussion was aimed mainly at pyelonephritis, with queries on other facets of genito-urinary pathology being mentioned. A review of the literature reveals that pyelonephritis is the commonest cause of death in uremia. While it kills twice as many patients as glomerulonephritis, it occupies only about a third of the literature given to these two problems. The statistics of a number of widely accepted authorities reveals that of all the patients admitted to hospitals, 1% have a urinary tract infection and 5% of all patients treated by pediatric services have a urinary tract infection. Pyelonephritis is more common in the female than in the male in the ratio of 9:1. In the female it is more common in the years from 0-12 and from 25-70 years of age. Very few males have pyelonephritis except those with congenital anomalies, and in the older age group those with gonorrheal obstructions and prostatic enlargement. The manifestations of congenital obstructions to urine flow usually present themselves in the ages from 0-6 years. CAUSES OF PYELONEPHRITIS Natural Causes The Short Rrethra of the Female: In females under 8 or 9 years of age, the urethra is about 1 cm long and some females have such a short urethra that it is essentially only a urethral sphincter. In 10 females less than 10 years of age, all 10 had dye in their bladders, after they sat down and stood up 20 times in 6 inches of dyed water. What is not understood is why more females do not get infection, if this is the answer to more frequent infections in females than in males. Overdistention of the Bladder: Marked overdistention of the bladder causes vesicoureteral reflux. This condition is more common in adolescents who do not have enough social experience, i.e. those who would not feel free to excuse themselves from company in order to urinate. Involuntary Residual Urine: In the male patient who has severe paraphimosis and dysuria, an increase in residual urine is often found. Also following circumcision, the skin of the glans penis often exfoliates, leading to urethral meatal ulceration causing dysuria which is followed by a residual urine.