The paper describes a number of developing country applications of economic instruments (EIs), focusing on how policy makers—mostly in Asia and Latin America—have addressed implementation problems. The informational and institutional demands of EIs can be as great as with regulations; in any event, the former are mostly used to complement not replace the latter. Consideration of political acceptability has conditioned both instrument design (e.g. grandfathering of tradable permits, non-compliance fees rather than simple pollution charges) and phasing of implementation (e.g. starting with local experimentation, setting low initial charge rates). With the advance of market-oriented economic reforms in the developing world, the policy and institutional environment should become more conducive to applying EIs; with greater political openness in many countries, the scope for involving the media, non-governmental organizations, and the public at large in environmental enforcement (e.g., through information disclosure programmes) should also increase.