The retention of students is a challenge faced by many universities in countries where participation rates are high. Living learning communities (LLCs) have been adopted by college administrators to increase retention, even though evidence of their effectiveness is largely anecdotal. This paper uses propensity score matching to address selection bias and identify the causal effect of an LLC program on GPA and retention. Survival analysis (of the matched sample) is used to estimate retention over time. Results suggest that the LLC program has a positive and lasting effect on retention and a positive impact on GPA in the earlier college years.