LIMES (Land/Sea Integrated Monitoring for European Security) is a FP6-funded project which aims at developing satellite-based services for a range of security-related applications such as maritime, land & border surveillance and emergency response. LIMES started in December 2006 and will run until early 2010. Most of the development work has now been concluded and was tested in a number of service demonstrations. LIMES contains a workpackage focused on Treaty Monitoring, which has the objective to provide an integrated platform supporting the Non-Proliferation image analyst in verifying treaty compliance. The main aspects addressed by the work package are: ? increased automation of the image processing workflow, in particular in the areas of object-based change analysis, 3D information extraction and processing of radar imagery. ? improved information management using a GIS-based platform capable of integrating information from multiple sources and time-frames, including satellite imagery, site models, open source information, reports, etc The Treaty Monitoring workpackage carried out two service demonstrations in 2008 and 2009 using the nuclear site Olkiluoto (Finland), which hosts a nuclear facility under construction. The demonstration scenario was the monitoring of construction activities using different types of satellite imagery as well as Open Source information. The demonstration and platform validation was performed at the European Satellite Centre (EUSC) and the results were presented to a number of potential users including IAEA and DG-TREN. The paper presents the achievements of the Treaty Monitoring workpackage and in particular the results of the platform demonstrations.