Mistreatment of medical students has long been a challenge in medical schools of variousrncountries. However, studies assessing the prevalence and its effects on students' perceptions ofrntheir professional development are scant in Ethiopia. Thus, this study is an attempt to contributernempirical evidence to fill this gap. Specifically, the paper probes the prevalence of exposure tornmistreatment among intern medical students at St. Paul Hospital Millennium Medical College,rnAddis Ababa, Ethiopia. Both quantitative and qualitative data were collected from primary andrnsecondary source. The data collected were analyzed and discussed using several descriptivernstatistics. The survey result revealed the presence of different types of mistreatment, which fairlyrnvaries between male and female students. The most important ones were yelling or shouting thatrnis offensive, harsh, or insulting speech on both male and female students and some sort of sexualrnharassment in only female students. Threat to unfair grade and giving some kind of negative orrndisparaging remarks are also types of mistreatments (closer to often) perceived and reported byrnstudents. The paper also find evidence that nurses and residents were most important source ofrnmistreatment in the learning environment. However, the reasons for such unprofessionalrnconducts were not very clear to most of them. The perceived effect of one or more types ofrnmistreatments were also analyzed and the result shows that medical students who experiencernmistreatment are found to have hurtful outcomes on their emotional security and professionalrnattitudes. Specifically, many students indicated to sometimes feel a sense of regret in choice ofrncareer or lack of satisfaction their educational experience, hating the health environment andrndepression and low self-confidence. Such feelings of distress during intern status of studies couldrnexacerbate the compromising quality of potential physicians and health care system. Qualitativernanalysis of data was also highly consistent with the above findings and used for triangulationrnpurpose. The study concludes by highlighting some short- and long-term recommendations thatrncan help the school develop policies and eradicate the widespread and complex mistreatmentrnphenomenon.