The Open University has been undertaking an extended initiative to improve student retention through enhanced support for at-risk students. This initiative has evolved through a series of stages from ad hoc small scale local interventions relying largely on tutors and student self-referral, to an institution-wide pro-active system implemented by specialist staff, backed by cost-effectiveness data based on evaluations of controlled experiments, and driven by management information systems. This article will outline the similarities and differences between retention in distance learning in the United Kingdom (UK) and in United States (US) colleges, illustrate the way a program of planned interventions was evaluated at the Open University, explain how the cost-effectiveness of interventions was established, and describe the integrated proactive system now in operation. (Contains 6 tables.0