November 1998 Secure property rights to land and well-functioning land rental and sales markets are essential for creating investment incentives, improving the allocation of land, and developing financial markets. Yet regulatory restrictions on land rental and sales and regulatory frameworks providing inadequate tenure security are common. This paper looks at the impact of imperfections in other factor markets and the costs and benefits of government intervention to improve the security of property rights and the functioning of land markets and draws conclusions about land policy issues. In agrarian societies land serves as the main means not only for generating a livelihood but often also for accumulating wealth and transferring it between generations. How land rights are assigned therefore determines households' ability to generate subsistence and income, their social and economic status (and in many cases their collective identity), their incentive to exert nonobservable effort and make investments, and often their ability to access financial markets or to make arrangements for smoothing consumption and income. With imperfections in other markets, the institutions governing the allocation of land rights and the functioning of land markets will have implications for overall efficiency as well as equity. The authors examine how property rights in land evolve from a situation of land abundance. They discuss factors affecting the costs and benefits of individual land rights and highlight the implications of tenure security for investment incentives. They also review factors affecting participation in land sales and rental markets, particularly the characteristics of the agricultural production process, labor supervision cost, credit access, the risk characteristics of an individual's asset portfolio, and the transaction costs associated with market participation. These factors will affect land sales and rental markets differently. Removing obstacles to the smooth functioning of land rental markets and taking measures to enhance potential tenants' endowments and bargaining power can significantly increase both the welfare of the poor and the overall efficiency of resource allocation. Drawing on their conceptual discussion, the authors draw policy conclusions about the transition from communal to individual and more formal land rights, steps that might be taken to improve the functioning of land sales and rental markets, and the scope for redistributive land reform. This paper--a product of Rural Development, Development Research Group--was prepared as background for the forthcoming Handbook on Agricultural Economics. The authors may be contacted at [email protected] or [email protected].