This research examines the effects of an off-campus service learning program on the moral reasoning development of college students. A pre-post quasi-experimental design was employed with two groups of college students (aged 18-22), one that engaged in service learning and the other which did not. The intervention was an eight-week summer service project that took place in one of several cities in the US, coupled with a continuing reflection component completed during the fall semester following the service project. The service learning and comparison groups completed the Defining Issues Test (DIT-2) before and after the service learning course. Findings revealed no differences between the two groups' pre test moral reasoning scores. Regarding post-test scores, the service learning group had statistically significant higher moral reasoning than the comparison group. (Contains 1 table and 1 figure.)