For the past two decades, evidence-based medicine (EBM), or the reliance on current scientific evidence to reach medical decisions, has been embraced as a new paradigm to standardize clinical care. Drawing from in-depth interviews with seventeen pediatric residents in two residency programs, we evaluate the extent to which the medical sociology scholarship on uncertainty analytically elucidates the recent influx of EBM during residency training. Our findings suggest that residents interpret EBM in varying ways to match their work practices: "Librarians" consult the literature while "researchers" evaluate it critically. For both groups, EBM might generate new uncertainties due to the increased reliance on information technologies and epidemiology. Whether EBM reduces uncertainty depends upon the residents' understanding of standardized knowledge and consequent incorporation of EBM in their clinical practice. Contrary to the predictions of some sociologists, EBM does not lead to a diminishment of humanitarian values in medical care. Nor does EBM lead to a science-based meritocracy on the patient ward, as claimed by some EBM advocates. Our conceptual updating of uncertainty emphasizes the continuous management of uncertainty during the medical socialization process. We argue that managing uncertainty develops along with what we term evidence-based clinical judgment.