To benefit fully from integration into the world economy, developing countries need basic public goods and services: transportation infrastructure, information and communications technology systems, trade facilitation mechanisms, standards certification bodies, and developed markets. Where small, poor governments lack the capital and expertise to provide such services, public-private partnerships have proven an effective alternative. In such a partnership, the private sector supplies the expertise, while the public sector ensures that investments are in the public interest, not subject to private sector monopoly, and consistent with long-term objectives.In this paper we describe the importance of public-private partnerships. Using case studies, we describe common challenges and suggest conditions necessary for success.