Background: Moral distress is a reason for burnout in healthcare professionals, but the clinical settings in which moral distress is most often experienced by medical students, and whether moral distress is associated with burnout and career choices in medical students is unknown. We assessed moral distress in medical students while caring for older patients, and examined associations with burnout and interest in geriatrics. Methods: A cross-sectional survey study of second-, third-, and fourth-year medical students at an American medical school. The survey described 12 potentially morally distressing clinical scenarios involving older adult patients. Students reported if they encountered each scenario, and whether they experienced moral distress, graded on a 1-10 scale. We conducted a principal axis factor analysis to assess the dimensionality of the survey scenarios. A composite moral distress score was calculated as the sum of moral distress scores across all 12 scenarios. Burnout was assessed using the Maslach Abbreviated Burnout Inventory, and interest in geriatrics was rated on a 7-point Likert scale. Results: Two-hundred and nine students responded (47%), of whom 90% (188/209) reported moral distress in response to ≥1 scenario with a median (IQR) score of 6 (4-7). Factor analysis suggested a unidimensional factor structure of the 12 survey questions that reliably measured individual distress (Cronbach alpha = 0.78). Those in the highest tertile of composite moral distress scores were more likely to be burnt out (51%) than those in the middle tertile of scores (34%), or lowest tertile of scores (31%) (p = 0.02). There was a trend towards greater interest in geriatrics among those in the higher tertiles of composite moral distress scores (16% lowest tertile, 20% middle tertile, 25% highest tertile, p-for-tend = 0.21). Respondents suggested that moral distress might be mitigated with didactic sessions in inpatient geriatric care, and debriefing sessions with peers and faculty on the inpatient clerkships on medicine, neurology, and surgery, where students most often reported experiencing moral distress. Conclusions: Moral distress is highly prevalent among medical students while caring for older patients, and associated with burnout. Incorporating geriatrics education and debriefing sessions into inpatient clerkships could alleviate medical student moral distress and burnout.