We describe a Service-Learning (S-L) course for freshman biological science majors and report self-reported assessment of student learning. Students were placed in K-12, STEM-oriented educational service positions. Course topics and service experiences were integrated using a weekly blog and class discussions. Through anonymous TRACE surveys, students reported higher course rigor and learning than students in other introductory biology courses and in anonymous S-L surveys, students indicated that S-L specifically enhanced their biology learning. Analysis of student writing from the fall 2011 course showed that increased biological knowledge was the most commonly reported learning gain from the S-L and that S-L was a major contributor to student learning. Taken together, these results suggest that Service-Learning can be utilized to specifically deepen learning in biology in addition to strengthening professional skills and civic engagement.