Permafrost is a subsurface phenomenon whose ground thermal regime is mainly influenced by air temperature, land cover, soil and rock properties and snow parameters. Many spaceborne applications are potentially indicative for the thermal state of Permafrost, such as ‘land surface temperature’, ‘surface moisture’, ‘freeze/thaw’, ‘terrain’, ‘vegetation’ and ‘changes of surface waters’. The major task of the ESA Data User Element Permafrost project is to develop circumarctic/-boreal Earth Observation services of these parameters with extensive involvement of the permafrost research community. The DUE PERMAFROST datasets will be processed in the EO-PERMAFROST Information System and provided via a WebGIS-interface. Further information is available at www.ipf.tuwien.ac.at/ permafrost. In order to set up the required validation tasks and information services, a target area approach with specified case study regions is used. Most of the foreseen DUE PERMAFROST remote sensing applications are well established and can optimally become operational. The goal of DUE PERMAFROST is to lend confidence in their scientific utility for high-latitude permafrost landscapes. Therefore, a major component is the evaluation of the DUE PERMAFROST products. Ground measurements in the high-latitude landscapes involve challenging logistics and are networked on multidisciplinary and circum-arctic level by the Permafrost community. The International Permafrost Association (IPA) has built up the Global Terrestrial Network for Permafrost (GTN-P) that is a network of the Circumpolar Active Layer Monitoring (CALM) and the Thermal State of Permafrost (TSP) projects. A major part of the DUE PERMAFROST core User group is contributing to GTN-P. Additional members of these programs and circum-arctic networks have also been involved in the consulting process and ground data providing process. Match-up data sets of ground data and remote sensing products coincident in time and location are being built up. The test regions are the Laptev Sea Region (RU) (continuous very cold permafrost/tundra), the Yakutsk Region (RU) (continuous cold permafrost/taiga), the Alaska Highway Transect (US) (continuous to discontinuous/ taiga-tundra), the West Siberian transect (RU) (continuous to discontinuous/ taiga-tundra) including Yamal Peninsula and Ob Region, and the Mackenzie Delta and valley Transect (CA) (continuous to discontinuous/taiga-tundra). There are no standard evaluation methods for all the diverse remote sensing products, specifically not for these latitudes. Evaluation experiments and intercomparison is done on a case-by-case basis, adding value and experience in validating products for these regions by addressing following questions: (1) Are plot data representative of surrounding parameters at satellite spatial resolutions? (2) How are the statistics derived from the matchup analysis against in-situ Diagnostic Data Sets (DDS) (absolute validation)? (3) How is the credibility of DUE Permafrost products against ‘descriptive truth’ (relative validation)? This paper focuses on the validation activities in the Lena Delta (Laptev Sea region). UR: www.ipf.tuwien.ac.at/permafrost