Background: Climate change is likely to increase the threat of wild fires, and little is known about how wild fires affect health in exposed communities. A better understanding of the impacts of the resulting air pollution has important public health implications for the present day and the future. Method: We performed a systematic search to identify peer-reviewed scientific studies published since 1986 regarding impacts of wild fire smoke on health in exposed communities. We reviewed and synthesized the state of science of this issue including methods to estimate exposure, and identified limitations in current research. Results: We identified 61 epidemiological studies linking wild fire and human health in communities. The U.S. and Australia were the most frequently studied countries (18 studies on the U.S., 15 on Australia). Geographic scales ranged from a single small city (population about 55,000) to the entire globe. Most studies focused on areas close to fire events. Exposure was most commonly assessed with stationary air pollutant monitors (35 of 61 studies). Other methods included using satellite remote sensing and measurements from air samples collected during fires. Most studies compared risk of health outcomes between 1) periods with no fire events and periods during or after fire events, or 2) regions affected by wild fire smoke and unaffected regions. Daily pollution levels during or after wild fire in most studies exceeded U.S. EPA regulations. Levels of PM 10, the most frequently studied pollutant, were 1.2 to 10 times higher due to wild fire smoke compared to non- fire periods and/or locations. Respiratory disease was the most frequently studied health condition, and had the most consistent results. Over 90% of these 45 studies reported that wild fire smoke was significantly associated with risk of respiratory morbidity. Conclusion: Exposure measurement is a key challenge in current literature on wild fire and human health. A limitation is the difficulty of estimating pollution specific to wild fires. New methods are needed to separate air pollution levels of wild fires from those from ambient sources, such as transportation. The majority of studies found that wild fire smoke was associated with increased risk of respiratory and cardiovascular diseases. Children, the elderly and those with underlying chronic diseases appear to be susceptible. More studies on mortality and cardiovascular morbidity are needed. Further exploration with new methods could help ascertain the public health impacts of wild fires under climate change and guide mitigation policies.