<p>To improve patient safety, hospitals have implemented interventions to change their culture. Although there is great enthusiasm for these interventions at policy and management levels, we know little about how clinicians talk about "culture" as they do the work of quality and safety improvement. This article investigates the way talk of culture arises in situ, showing how it is a trope that can frustrate, obscure, and prevent the collective social action necessary to change practice. The findings are based on a two-year ethnographic case study of a large hospital in the United States that undertook an organization-wide safety improvement initiative. They show that culture is frequently talked about as a behavioral trait of individuals, which makes the identification of social barriers and facilitators difficult. Culture talk can also obscure uncomfortable, yet crucial social phenomena, including history, politics and inequalities in power that may contribute to unsafe care delivery. The consequences of this obscurity are (1) practices that might make care safer are not considered, and (2) responsibility for enacting safe practice is allocated to those with the least authority and capacity to mitigate risk. The article closes by discussing how talk of culture obscures the role of social context and its contribution to risk in patient safety.</p>