The authors conducted a chart review of all febrile infants between 28 and 90 days of age who presented to the emergency department (ED) between December 1 and March 31 during 2004-2006. The objectives of the study were to describe the practice patterns of pediatric ED physicians caring for these infants and to determine whether the evaluation and management of these infants differed based on their age at presentation. Two groups were compared-infants aged 28 to 59 days (n = 79) and infants aged 60 to 90 days (n = 88). As compared with the younger age group, infants in the older age group had fewer complete blood cell counts (relative risk, RR = 3.57; 95% confidence interval [CI], 2.15-5.95), fewer blood cultures (RR = 3.38; 95% CI, 1.99-5.74), fewer urine cultures (RR = 3.83; 95% CI, 1.81-8.13), and fewer cerebrospinal fluid cultures (RR = 2.56; 95% CI, 1.94-3.40). Overall, there was poor adherence to current guidelines for the diagnostic evaluation of young febrile infants.