This paper investigates the issue of adoption and use of Knowledge Management (KM) practices by Knowledge-Intensive Business Services (KIBS) companies, i.e. private companies whose job consists of collecting, generating, analysing, and distributing knowledge with the purpose of developing customized services or solutions to satisfy the needs of business clients. KIBS companies rely on highly educated professionals, experts on specific technical disciplines or functional domains, and supply knowledge-based services. Knowledge is their major resource that allows developing new competencies and constitutes a precondition for the delivery of new services. This is the reason why the issue of KM applied to KIBS should have a central relevance for scholars and practitioners. Nevertheless, the research on this topic is still scarce. Furthermore, one would expect that KIBS firms accurately manage their knowledge base, also by means of formal practices, but the (few) empirical studies indicate that KIBS companies often lack systematic methods for managing their knowledge. Consequently, there is the need to analyse the issue of KM in KIBS more thoroughly. In light of this, the paper discusses the findings of a survey involving 471 KIBS located in North-Eastern Italy and operating in three different subsectors: ICT Services, Design and Communication, Professional Services. In particular, the study: a) analyses how internal knowledge is handled by the surveyed companies; b) investigates the main sources of external knowledge the companies make use of; c) examines the relationship between the way KIBS companies manage their knowledge assets and the kind of service they supply. The outcomes of the investigation may have important implications both from an academic and a managerial viewpoint. Especially, as regards the latter, it can provide KIBS firms with food for though concerning the use of appropriate KM approaches for sustaining their business activity.