Abstract While federal rulemaking is an essential part of American governance, it is not well understood by researchers and advocates. We surveyed 115 former regulators at the Environmental Protection Agency to understand their views on the kinds of information they valued most and their communication preferences (June – August 2023). Respondents highly valued information about the scope of a problem (93%), legal analysis (96%), technology assessments (93%), and impacts of a proposed rule (97%). Regulators had difficulty accessing several kinds of information: 16% of respondents viewed racial equity information as easy to access and 28% thought financial information was easy to access. Respondents valued communications that provided data (99% viewed as effective), made compelling arguments (96%) or technical recommendations (91%), and storytelling (88%). Respondents indicated that the content of comment letters was important: 92% viewed letters containing data as important, and 90% valued technical recommendations. Only 22% thought that repetition of the same comments across letters was important. Our findings reveal opportunities for researchers and advocates to help fill information gaps and identify communication strategies that might resonate with federal regulators.