Evaluation researchers have confirmed the importance of conference evaluation, but there remains little research on the topic, perhaps in part because evaluation methodology related to conference impact is underdeveloped. We conducted a study evaluating a 4-day long health conference, the Second Global Symposium on Health Systems Research (HSR), which took place in Beijing in November 2012. Using a conference evaluation framework and a mixed-methods approach that involved in-conference surveys, in-conference interviews and 7-month post-conference interviews, we evaluated the impact of the Symposium on attendees’ work and the field of health systems research. The three major impacts on participants’ work were new knowledge, new skills and new networks, and many participants were able to provide examples of how obtaining new knowledge, skills or collaborations had changed the way they conduct their work. Participants noted that the Symposium influenced the field of HSR only in so far as it influenced the capacity of stakeholders, but did not lead to any high level agenda or policy changes, perhaps due to the insufficient length of time (7 months) between the Symposium and post-conference follow-up. This study provides an illustration of a framework useful for conference organizers in the evaluation of future conferences, and of a unique methodology for evaluation researchers.