Early childhood education (ECE) interventions hold great promise for not only improving lives but also for potentially producing an economic return on investment linked to key outcomes from program effectiveness. Assessment of economic impact relies on accurate estimates of program costs that should be derived consistently to enable program comparability across the field. This is challenged by a lack of understanding of the best approach to determine program costs that represent how they will occur in the real world and how they may vary across differing circumstances. Thorough and accurate cost analyses are vital for providing important information toward future implementations and for enabling analysis of potential return on investment. In this paper, we present five key issues most relevant to cost analysis for ECE programs that interventionists should acknowledge when estimating their programs' costs. Attention to these issues more broadly can lead to comprehensive and thorough cost estimates and potentially increase consistency in cost analyses. These issues are illustrated within the cost analysis of REDI (Research-based, Developmentally Informed), an enrichment program that seeks to extend the benefits of preschool through enhanced classroom and home visiting services. Implications for practice and policy are discussed. (author abstract)