While tutoring as a whole has been demonstrated to improve student learning across a variety of subjects and age groups, there is little published evidence for the effectiveness of drop-in tutoring at the undergraduate level. This type of tutoring can be derided as homework help; however, it is clear from this study that students who made use of the Tutoring Center (TC) regularly gained more academically than simply help with an individual class. In fact students who visited the TC more than 10 times per quarter had approximately 10% higher rates of persistence and approximately 0.2 points higher average GPA's than students who infrequently visited or who do not visit the TC during their first year of college. (Contains 8 tables and 5 figures.)