Medical students’ concerns during clinical clerkships may not always be addressed with mentors who work under significant time constraints. This study examined 3rd year students’ survey responses regarding patient encounters to elucidate what may be hidden aspects of their learning environment. We analyzed results to an 18-item survey completed during a required ethics and professionalism course in third-year medicine clerkships over a period of 18 months. The survey covered types of concerns elicited by patient encounters, interactions with mentors about concerns, (...) perceptions of mentors, and level of moral distress. We also examined results of a 7-item evaluation of small group discussions during the study period. 1210 surveys and 195 evaluations constituted the study samples. Students’ concerns related primarily to ethics (36.4%, n = 441) and quality of care (34.5%, n = 418). Concerns had not been raised with a mentor in 535 (44.2%) instances. Students experienced moral distress in connection with 35.4% (n = 324) of cases; this was particularly common when a concern applied to a mentor. Higher levels of moral distress were associated with a lower likelihood of wishing to emulate the mentor (r = -0.27, p <.001). Two thirds of students, 66.9% (n = 107), stated that small group discussions where concerns were discussed lowered their stress levels. We suggest that clinical mentors be made aware of students’ learning needs and that structured discussions be available for students to articulate concerns with peers and facilitators in efforts to uncover elements of the hidden curriculum with the goal of optimizing students’ well-being, learning and professional development. (shrink)