The study objectives were to characterize the infectious outcomes and associated clinical parameters of a large group of febrile young infants who received outpatient sepsis evaluation. This retrospective review of consecutive cases during a seven-year period was set in an urban pediatric emergency department. Febrile infants, aged zero to eight weeks, were the participants. All received a standard evaluation for sepsis, including complete blood count/blood culture, lumbar puncture/cerebrospinal fluid culture, and urinalysis/urine culture. Of 1130 patients, 447 (42%) were aged zero to four weeks, and 683 (58%) were aged four to eight weeks. In 96 cases (8.5%), a bacterial pathogen was isolated by culture of cerebrospinal fluid, blood, urine, or stool; 58% were aged zero to four weeks and 42% were aged four to eight weeks. The rate of positive cultures per patient age was doubled in those aged zero to four weeks (12%) compared with those aged four to eight weeks (6%). The 49 cases of invasive bacterial infections (bacterial meningitis/bacteremia) were most commonly associated with lower degrees of fever, as slightly over one half (25/49) had temperature < 39 degrees C. The most common pathogens of invasive bacterial infection were group B streptococcus and Escherichia coli, accounting for 33 of 49 cases (67%); the most common pathogens of invasive bacterial infection in older children (Haemophilus influenzae type b and Streptococcus pneumoniae) were relatively underrepresented, accounting for only five of these 49 (10%) cases.