The objective of the study was to examine available evidence on healthcare providers' willingness to report to work during a pandemic influenza and on related measures. Limited to scholarly journals, a search in nine databases produced 206 studies, 28 of which met inclusion criteria and were discussed in depth this review. Six studies posed an avian influenza scenario, four studies were conducted during the 2009/2010 global H1N1 pandemic influenza and the remaining 18 studies examined willingness to report to work under a scenario that was related to a pandemic influenza but the type of flu was under-specified. Willingness to report to work varied dramatically among the 28 studies, from a low of 23.1% to a high of 93.1%. Heterogeneous methods employed by researchers make it hard to generalize and draw practical conclusions. Preliminary evidence suggests that physicians may be more willing to report to work than nurses. Given the current state of the literature and the need to estimate workforce availability for preparedness planning, worst case scenario planners may cautiously assume that 1 in 4 healthcare providers will be willing to report to work during a pandemic influenza, not accounting for those who are ill. Because physicians demonstrated higher willingness, the 1 in 4 estimate could be adjusted upward for this provider group.