IMPORTANCE: Medical aid in dying (MAID) is legal in jurisdictions covering more than one-fifth of the US population and has been used by a largely White, educated population. The extent to which knowledge of MAID and preferences for personal use align with patterns of use is unknown. OBJECTIVE: To evaluate knowledge among US adults of the legal status of MAID as well as interest in using MAID. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional, self-report online survey study used a national Prime Panels-based sample of US adults recruited between July 16 and August 10, 2024. A total of 3227 respondents aged 18 years or older from all US states and Washington, DC, were included. Individuals from states with legal MAID, aged 60 years or older, and members of racial and ethnic minority groups were oversampled. MAIN OUTCOMES AND MEASURES: Knowledge of the legality of MAID in the US and in respondents' state of residence as well as potential interest in future use of MAID. Descriptive statistics and χ2 tests were used to examine associations by demographic characteristics and place of residence. RESULTS: Of 3227 respondents (mean [SD] age, 55.7 [17.4] years
1839 women [57.0%]), 1654 (51.3%) did not know if MAID was legal the US, and 1638 (50.8%) did not know if MAID was legal in their state. Respondents in states where MAID is legal were more likely to know that MAID is legal in the US compared with those in states where MAID is not legal (728 of 2164 [33.6%] vs 216 of 1063 [20.3%]
P <
.001). Across all respondents, 1420 (44.0%), including 96 of 222 Asian respondents (43.2%), 206 of 605 Black respondents (34.0%), and 129 of 308 Hispanic respondents (41.9%), reported they would definitely or probably consider MAID if they received a diagnosis of a terminal illness. CONCLUSIONS AND RELEVANCE: In this online survey study of US adults, substantial interest in using MAID as well as significant knowledge gaps regarding the legality of MAID were reported. These findings highlight the need for public education, policy initiatives, and patient-clinician discussions to ensure equitable access to patient-centered end-of-life options and informed decision-making.