In today's business environment, building networks can represent a suitable strategy in order to enhance the competitiveness of the partners involved. Knowledge sharing in networks allows the creation and development of knowledge, having become the most valuable resource for any type of organisation. However, there must be effective and efficient management to encourage this phenomenon. This holds in particular in the healthcare sector, which at present is marked by increasing cost pressures while being challenged to maintain its level of social responsibility. Consequently, here a more thorough understanding of networks as a facilitator for the sharing of knowledge becomes necessary. Despite considerable research in networks, only a few studies have dealt with their impact on knowledge sharing processes in the healthcare sector. In particular, little effort has been put into developing a valid and reliable measure of knowledge sharing in the healthcare context. Hence, the objective of our paper is to propose and evaluate an instrument for measuring knowledge sharing in networks as facilitators of Knowledge Management Capabilities (KMC). In doing so, we used the following procedures: (a) identifying individual items, (b) developing constructs and (c) empirically validating the scale. For the latter, a quantitative survey design was chosen. The questionnaire was answered by a final sample of 202 professionals in clinical analyses and public health, all working in different healthcare organisations in Portugal. The results reveal high factor loadings and acceptable Cronbach's alpha coefficients, indicating validity of the two-factor structure (Knowledge Acquisition and Knowledge Transfer) we detected. In theoretical aspects, our research serves to induce further investigations on networks as knowledge transfer mechanisms in other contexts by applying the psychometric instrument. From a practical viewpoint, by using the two-factor structure as an analytical tool, managers can diagnose shortcomings in their inter-organisational networks and in this way optimise their knowledge management strategies and practices.