Building knowledge in professional organizations involves complex discursive practices. In 2014 a group of employees at the Public Health Agency of Canada (PHAC), including senior managers, project facilitators, and other staff members, collaborated in managing a communication problem involving PHAC’s scientists and policy writers, an effort known as the Science to Policy Project. This study investigates how an activity system, with its genre set, was used to build knowledge regarding the causes of the problem and also possible solutions. As well, the study looks at key genres from the government-wide genre system in which this activity of knowledge-building was situated. At the same time, the study describes PHAC’s attempt to implement a new organizational culture to facilitate the knowledge-building activity the employees were engaged in.