In the present study, we investigated how two team mental model properties (similarity vs. accuracy) and two forms of monitoring behavior (team vs. systems) interacted to predict team performance in anesthesia. In particular, we were interested in whether the relationship between monitoring behavior and team performance was moderated by team mental model properties. Thirty-one two-person teams consisting of anesthesia resident and anesthesia nurse were videotaped during a simulated anesthesia induction of general anesthesia. Team mental models were assessed with a newly developed measurement tool based on the concept-mapping technique. Monitoring behavior was coded by two organizational psychologists using a structured observation system. Team performance was rated by two expert anesthetists using a performance-checklist. Moderated multiple regression analysis revealed that team mental model similarity moderated the relationship between team monitoring and performance; a higher level of team monitoring in the absence of a similar team mental model had a negative effect on performance. Furthermore, team mental model similarity and accuracy interacted to predict team performance. Our findings provide new insights on factors influencing the relationship between team processes and team performance in health care. When investigating the effectiveness of a specific team coordination behavior, team cognition has to be taken into account. This represents a necessary and compelling extension of the popular process-outcome relationship on which previous teamwork research in health care has focused. Moreover, the current study adds further external validity to the concept of team mental models by highlighting its usefulness in health care.