Surveys are an important tool for assessing physician and nursing professionals’ practice patterns and guideline adherence. Obtaining quality survey data consisting of low item and unit nonresponse remains a persistent challenge in these populations. We tested the relative impact of two envelope types (padded vs. priority mail) on unit and item nonresponse in a survey of Minnesota health care workers. Respondents were randomized to receive a survey in one of two envelope types: a padded 8.5'' x 11'' envelope or a similarly sized priority mail envelope. After the first mailing, the response rate was 53.9% and did not differ across envelope conditions. Females and RNs were more likely to respond to the priority envelope than the padded envelope, but this finding did not hold in multivariate analysis. There was no difference in item nonresponse across the two envelope conditions. It may be that our two approaches were not enough to permeate the semi-porous membrane of gatekeeping that has been posited as a driver of low physician survey response rates relative to those observed in the general population. Nonetheless, our findings suggest that packaging may matter for some populations and not others.