This paper presents the results of a communicational study of High Reliability Organizations (HRO). Starting from a gap in the HRO literature, we seek to deepen the understanding of communicational nature of interactions within HROs. In particular, we contribute to the question related to the track: What forms of talk do we find in organizational practice, and how do they differ in shaping and constituting organizational phenomena in our study of reliability? We draw on the concept of ventriloquism (Cooren, 2010) and examine its impact and importance on the production of high reliability. We base our work on two empirical case studies. The first concerns heavy handling activity in a naval defense industry, and the second concerns the care provided to demented patients in a short-term geriatric ward. We use actor network theory, or ANT (Latour, 2005), to build an original analysis framework of ventriloquism that qualifies the figures in terms of “actor”, “actant” or “object.” Through a comparative approach, we show that ventriloquism can serve or disserve the high reliability of an organization. Specifically, we demonstrate that the nature of the object of activity (Engeström, 1987) is a crucial element for the relevance of ventriloquism. We describe the impact of ventriloquism on HROs and build a preliminary typology of talk practices that foster it. We conclude by discussing the theoretical, methodological and practical contributions of our research.