Tropical coastal resources including coral reefs, mangroves and seagrass beds are some of the most productive ecosystems in the World. They support a variety of goods and services that may often form the backbone of the local community. In many cases they provide the main source of food, as well as providing employment and recreation opportunities. However, coastal ecosystems are increasingly under threat from high population growth rates, rapid coastal development, over exploitation of the resources, loss of critical habitats and vulnerability to natural hazards. These tropical ecosystems are sensitive and vulnerable to damage and environmental change. Their worldwide loss has led to cause for concern and widespread calls for improved management. Integrated coastal management (ICM) is seen as the way forward in dealing with this complex mix of interests, activities and demands being placed on today's coastal zones. The definition of the coastal zone will vary between locations, ideally capturing and enabling the resolution of all major coastal issues, reaching as far inland or seaward as is required to reach the goals and objectives of the management programme. ICM encompasses the management of all aspects of the coastal zone taking a multi-disciplinary approach. It includes the management of existing economic activities, planned developments, natural resource conservation and utilisation as well as being able to deal with the different user conflicts. ICM involves the integration of different institutions and stakeholder groups at and across the local to international management levels. Even though ICM efforts are increasing, there are few examples where it is really being implemented and working effectively. In this study, three ICM case studies identified similar patterns of impediments although their scope was recognised as too narrow to make generalisations. As a result, a survey was developed to build up a broader picture of the issues blocking the development of successful ICM at several locations. The survey identified the current status of ICM in the tropics and identified the main impediments to implementing effective ICM. The survey found that few locations were actually implementing, monitoring and evaluating ICM, however a number were in the process of it. It was the step between analysis and implementation that was halting many of these efforts. Tropical coastal zones can be seen to share a number of common challenges exacerbated by poverty and conflicts between coastal users. Conflict management needs to be incorporated into the management process in a way that pays particular attention to the over-extraction of resources and destructive resource use. Although the concept of integrated coastal management (ICM) has been identified as the way to deal with the multiple objectives, interests and uses of the coastal zone, in practice it is a complex process and many countries are having difficulty in implementing ICM. The most common impediments to ICM in the tropics were identified through the survey as were their impact on implementing ICM. The extent to which ICM is achieved can be linked to the impediments, described by a series of criteria, which could be used in assessing the ability of an area to implement ICM as well as identifying priority areas for concern. The results show that although public participation is commonly accepted as a major part of ICM and is one of the main impediments, it is rarely fully realised. Gaining political support and empowering agencies with sufficient authority to enforce ICM were also identified as major impediments, without which ICM efforts may well be blocked. Decision making for integrated coastal managementin volves multiple decision makers and multiple stakeholders, often with conflicting needs and interests. Decision support systems (DSS) can be developed to improve our understanding of the inter-relationships between the natural and socioeconomic variables and hence result in improved decision making. The question is whether this decision making environment is actually too complex for the development of useful and useable decision support systems. An ICM-DSS needs to be able to involve multiple decision makers and take into consideration multiple issues. This requires different disciplines to be drawn together into an integrated modelling framework. There are many techniques available to deal with different modelling needs, the constraints of inadequate data and the multi-objective decision making environment. There are also different ways of developing decision support systems and each can play a different, but nonthe- less important role within ICM. Three coastal DSSs were evaluated in terms of their design and roles in integrated coastal management and are used to evaluate the potential to develop ICM-DSSs. One of these DSSs, CORAL, is examined in detail as a case study. The model is an example of an integrated ICM model where the final result is a score-card of criteria that measure economic, environmental, social and institutional objectives. CORAL was developed for the island of Curacao in the Caribbean and the Republic of the Maldives. The development process involved stakeholder meetings and interviews to ensure that all their interests and concerns in the coastal zone were accounted for and included in the DSS. The model development was carried out in the Netherlands and on return was presented to the stakeholder groups. A second phase of the project in Curacao allowed the model to be installed on a wide number of computers. An ICM course was established as well as individual training given to the stakeholder groups involved. However, the final use of the DSS was still limited. Lessons are drawn from the CORAL experience that may assist in the development of future DSSs such as the need to involve a key organisation in the development and enable them to continue its development and maintenance after the end of the project. In addition, flexibility, adaptability and update-ability are paramount if the system is to be used beyond educational goals. The impact of ICM on a coastal system is not always readily measured and quantified, least of all in monetary terms. Economic valuation is being increasingly applied to tropical coastal ecosystems to assess their benefits in monetary terms. From the point of view of ICM, economic valuation could give monetary values to, for example, changes in production resulting from management and hence highlights the importance of management. Likewise, it can highlight the costs of inaction by quantifying the benefits of a situation with ICM and one without ICM. This not only requires the ability to link monetary values to certain environmental situations but also to model the potential changes in goods and services provided by the ecosystem as a result of management. Past analyses in ICM have often focused on the costs of management versus economic gains while change to the environment has been measured in physical terms. Economic valuation provides a potential to compare like with like and hence bring the importance of ecosystems, such as coral reefs, to the fore. Some goods provided by these coastal ecosystems are marketed and consequently have a marketdefined value associated with them. However, these ecosystems also provide a number of non-use benefits, which are not directly marketed and as a result, certain economic techniques have been developed to deal with these issues. The contingent valuation methodology (CVM) was developed as a tool to measure non-marketed goods and services of ecosystems so they can be included into costbenefit analyses. However, it is a complex technique surrounded by much controversy.