ALTHOUGH carefully controlled studies have shown that a clean voided sample of urine may be reliably obtained in more than three fourths of newborn and older infants of both sexes,1,2 our experience has been that when used routinely in the newborn nursery, clean voided urine specimens may give erroneous bacteriological results. Because we have been reluctant to catheterize newborn infants, we fortunately confirmed that under certain specific conditions infants urinate upon eliciting the Perez reflex.3 This led us to the use of this reflex in obtaining midstream urine specimens for bacteriologic investigation. Methods and Materials We studied 153 infants, 87 boys and 66 girls, between the first and fourth days of life. All infants were born at the University of Kentucky Hospital. Clean voided specimens were collected as follows: The nursery nurses were instructed to cleanse the genitalia by scrubbing the prepuce and glans penis in the boy