Health impact assessments (HIA) allow the potential impact of nonhealth-related actions (policy, project, program) on health to be analyzed. For example, municipal projects, for urban renewal or urban planning, have an impact on health drivers relating to the created environment, and thus, on public health. In the province of Quebec, the government and affiliated organizations have to comment on potential impacts; they use HIAs to ensure health is factored into public actions. We know little about HIAs' capacity to influence public policies; every policy and program is different and is often implemented only once, greatly complicating evaluation. Our goal is to analyze the potential of contribution analysis for evaluating the impact of HIAs at the municipal level. To this end, we present the HIA process as implemented in Montérégie, we identify evaluation challenges, and put forth, through contribution analysis, an evaluation strategy to analyze effects.