Current approaches to supporting awareness in computer-mediated collaboration appear to fall short in two ways - (1) they focus primarily on synchronous collaborations among individuals working on a shared task, and (2) they do not sufficiently take account of the situated and socially mediated nature of work practices. This paper explores an alternative approach to awareness support in computer-mediated collaboration, which focuses on understanding and supporting awareness of activity at the work practice level, and enables coordination among individuals working on separate tasks across communities of practice. We describe a study that suggests how an understanding of the ontological, stereotyped, and situated aspects of human activity leads to awareness support at the work practice level. We outline a set of guidelines for supporting practice-centred awareness in system design, and demonstrate the effectiveness of the approach in enabling decision support among clinicians working separately across boundaries of communities of practice. © 2014 IEEE.