This article aims to focus on the central role that the biomedical librarian has assumed in recent years in the world of research evaluation. Starting from the concept of bibliometrics, we examine the main traditional bibliometric indicators (impact factor and h-index) to arrive at the new alternative metrics (altmetrics). Librarians increasingly support evaluation activities and have the opportunity to reaffirm the key role of academic and non-academic scientific libraries as the place where research activity has always “pulsed”.