Permafrost and frozen grounds are key elements of the terrestrial cryosphere that will be strongly affected by a warming climate. This chapter presents an overview of the remote sensing methods for permafrost studies with current sensor technologies. It outlines the remote sensing methods in two permafrost environments that differ substantially in their character: mountain permafrost and lowland permafrost. For remote sensing of permafrost in mountain areas, evaluating surface features is the dominant remote sensing application. Remote sensing techniques employed in the vast arctic and subarctic lowland areas, however, include a wide range of sensors that allow both mapping of surface features and monitoring of physical surface variables that can be used to assess the permafrost state. The chapter concludes with an outlook on thermal permafrost modeling using remotely sensed data sets as input.