A detailed development plan (DDP) is a legally binding plan that regulates the municipalities land use on a detailed level. The purpose with the DDP is to evaluate the suitability for development on land access, in order for municipalities to manage spatial planning and minimize environmental harm. If a DDP would likely cause a significant impact on the environment, an Environmental Impact Assessment (EIA) has to be produced. The aim of this thesis was to investigate how DDP and EIA processes are working on a local level in Sweden, and how the quality is reflected in the processes. More specifically, I investigated the role of EIA actors involved in the DDP process, as well as whether these processes are inadequate from an environmental conservation perspective. To investigate these issues, a document study was conducted as well as an interview study. The results from the study presents several shortcomings in both processes; examples of shortcomings were the lacking knowledge among the DDP and EIA actors in how to conduct the process, as well as interpreting and understanding the law.  Other observed shortcomings were the different levels of engagement among the plan administrators, the EIA performers and the County Administrative Board reviewers. Three important factors were recognized for achieving good processes. Firstly, the people involved need to have broad knowledge and good qualifications. Secondly, the actors must be able to communicate in a good and clear manner. Lastly, the third factor is a good process leader who brings together the DDP and EIA process.