Background To describe the preferences for disclosure of individual biomarker results among mothers participating in a longitudinal birth cohort. Methods We surveyed 343 mothers that participated in the Health Outcomes and Measures of the Environment Study about their biomarker disclosure preferences. Participants were told that the study was measuring pesticide metabolites in their biological specimens, and that the health effects of these low levels of exposure are unknown. Participants were asked whether they wanted to receive their results and their child's (...) results. In addition, they were asked about their preferred method (letter vs in person) and format (more complex vs less complex) for disclosure of results. Results Almost all of the study participants wanted to receive their individual results (340/343) as well as their child's results (342/343). However, preferences for receiving results differed by education level. Mothers with less than a college degree preferred in-person disclosure of results more often than mothers with some college education or a college degree (34.3% vs 17.4% vs 7.9%, p<0.001). Similarly, mothers with less than a college education preferred a less complex disclosure format than mothers with some college education or a college degree (59.7% vs 79.1% vs 86.3%, p<0.0001). Conclusion While almost all study participants preferred to receive results of their individual biomarker tests, level of education was a key factor in predicting preferences for disclosure of biomarker results. To ensure effective communication of this information, disclosure of biomarker results should be tailored to the education level of the study participants. (shrink)