Abstract Background We sought to identify factors that affect the passage of public health legislation by examining the use of arguments, particularly arguments presenting research evidence, in legislative debates regarding workplace smoking restrictions. Methods We conducted a case-study based content analysis of legislative materials used in the development of six state workplace smoking laws, including written and spoken testimony and the text of proposed and passed bills and amendments. We coded testimony given before legislators for arguments used, and identified the institutional affiliations of presenters and their position on the legislation. We compared patterns in the arguments made in testimony to the relative strength of each state's final legislation. Results Greater discussion of scientific evidence within testimony given was associated with the passage of workplace smoking legislation that provided greater protection for public health, regardless of whether supporters outnumbered opponents or vice versa. Conclusion Our findings suggest that an emphasis on scientific discourse, relative to other arguments made in legislative testimony, might help produce political outcomes that favor public health.