The urinary beta(2)-microglobulin (MG) concentration on day 0 to 2 was significantly higher in premature infants with chorioamnionitis (CAM) than in infants without CAM and in infants who developed chronic lung disease (CLD) than in those who did not. We propose that an elevated urinary beta(2)-MG can indicate a fetal inflammatory response and identify neonates at risk for the development of CLD.