The financial mechanism within the European Union that is accessible for environmental issues is a tool by which it is possible to maintain and improve the state of the environment in the Baltic Sea region countries. However, the accessibility and use of finances cannot be considered indicators which mark the success of a programme. There are various evaluation types which can be conducted, such as ex ante to assess the impact desirable to help gauge what projects best to support. Ex post evaluations can also be applied to pool lessons learned to make recommendations for further development. Evaluation is important for checking progress, to further support successful initiatives and to avoid financing activities which do not produce results. Evaluation of environmental projects can be particularly difficult due to their diversity in approaches and applied technologies, however currently there is a risk to limit the assessment of projects to the activity-level (what outputs have been produced, such as number of seminars and publications or campaigns, technologies installed), rather than on the primary goal – specific impacts made on the environment. The goal of this research is to develop a methodology and set of indicators for the evaluation of environmental projects to improve the evaluation of project efficiency, impact and sustainability. Regional Cooperation Environmental Projects are selected and an evaluation is conducted on these projects.