Institutional predictors of volunteer service retention in AmeriCorps*State and National are assessed using data from the quasiexperimental, longitudinal study of AmeriCorps. Multilevel logistic regression is used, with individual member characteristics at the first level and institutional facilitation at the second level (across 107 program sites). Members are more likely to complete their terms of service if the program sites involve members in planning their service activities, match the activities to their career interests, help them develop a relationship with a mentor, and facilitate their reflection on the service experience with others. This study identifies strategies that may promote retention as an intermediate yet fundamental outcome.