Background. Surgical rotations for medical students have traditionally been service-based, with students observing surgical cases in an area of concentration specific to their assigned service. This may result in a lack of exposure to other surgical fields. To overcome this problem, students may rotate through focused "mini-rotations" in surgical subspecialties. We evaluated improvements in knowledge for students exposed to the two following types of surgical education: (1) traditional service-based rotations and (2) focused mini-rotations in a surgical subspecialty. Methods. Third-year medical students (n = 281) were assigned to a 4-week rotation on one of three services, with students on one service having a focused exposure to endocrine surgery. General surgical services included (1) surgical oncology/endocrine, (2) trauma, and (3) general surgery. In addition, all students were required to do a "mini-rotation" on vascular surgery for 2 days. To determine if there was a difference in learning between service-based (endocrine) versus mini-rotation-based (vascular) approaches to surgical education, a pre- and postrotation endocrine/vascular exam was administered. Results. Students with exposure to endocrine surgery had a 2-fold improvement in endocrine exam test scores (P = 0.001) compared to students on other general surgery services. There was no difference in vascular exam scores between students on different surgical rotations, reflecting the fact that all students had exposure to vascular surgery. Conclusion. Service-based rotations can lead to disproportionate learning experiences due to variations in exposure. "Mini-rotations" appear to equalize learning opportunities by providing all students with exposure to surgical subspecialties. These results suggest that educational experiences may be maximized by incorporating focused mini-rotations in surgical subspecialties. © 2005 Elsevier Inc. All rights reserved.