This publication offers a comprehensive collection of 70 "building blocks," which are primary prevention strategies that merit consideration by state and local governments and others in position to reduce exposure to hazards in housing and thereby help meet the Healthy People 2010 goal of eliminating childhood lead poisoning. Exemplary strategies span a broad spectrum which includes targeting high-risk properties; widely instituting safe work practices; building community capacity to check for hazards and work safety; delivering hazard assessment, control and prevention services; motivating action; screening high-risk housing; expanding financial resources; strengthening enforcement; raising public awareness and support; and establishing valuable partnerships. A strategy has been considered for inclusion as a building block if it is sensitive to the economics of affordable housing, consistent with the principles of public health, holds the potential for broad-scale impact, stands a reasonable possibility of implementation, and offers promise for reducing lead and other environmental health hazards in high-risk housing. The summary of each building block is coupled with an illustration of how the strategy has been implemented and contact information for at least one individual who is knowledgeable about this activity. The purpose of disseminating Building Blocks for Primary Prevention: Protecting Children from Lead-Based Paint Hazards is to allow programs and policymakers easy access to information about innovative and promising strategies that span the spectrum of primary prevention, from which they may select one or several to pursue based on their jurisdiction's needs and political and economic realities.