Software development in the grid: The DAMIEN tool-set The development of applications for Grid-environments is currently lacking the support of tools, which end-users are familiar with from their regular working environment. This paper analyzes the requirements for developing, porting and optimizing scientific applications for Grid-environments. A toolbox designed and implemented in the frame of the DAMIEN project which closes some of the gaps and supports the end-user during the development of the application and its day-to-day usage in Grid-environments is then presented.