Background Psychological distress in medical students is a global issue and poses a risk to their health, academic performance, and ability to care for patients as clinicians. There has been limited research on psychological distress levels in students prior to starting medicine and no direct comparison between undergraduate and graduate-entry students. Methods Psychological distress was assessed using the 21-item Depression Anxiety and Stress Scale in 168 undergraduate-entry and 84 graduate-entry medical students at two separated campuses of the same university in the orientation week prior to starting classes. Mean scores and severity proportions were compared between the two cohorts of students. Demographic data was also collected and compared to distress scores using subgroup analysis. Results The response rate for the study was 60.9%. The majority of undergraduate and graduateentry medical students were within the normal limits for depression (67.2% versus 70.2%, p = 0.63), anxiety (56.5% versus 44.0%, p = 0.06), and stress scores (74.4% versus 64.2%, p = 0.10). There was no significant difference between severity groups except for severe stress (2.3% versus 9.5%, p = 0.01). The mean scores of the clinically distressed groups indicated moderate levels of depression, moderate anxiety, and moderate stress scores. There were no significant differences between undergraduate or graduate-entry students for depressive (� x = 17.02 versus 15.76, p = 0.43), anxiety (� x = 14.22 versus 13.28, p = 0.39), and stress scores (� x = 20.83 versus 22.46, p = 0.24). Female gender and self-believed financial concerns were found be associated with higher levels stress in graduate entry students. Conclusions The majority of medical students enter medical school with normal levels of psychological distress. However, a large number of undergraduate and graduate-entry medical students