The potential of Synthetic Aperture Radar (SAR) images recorded withthe First European Remote Sensing Satellite (ERS-1) for sea iceclassification is investigated. The classification strategy employed is aregion-based segmentation with subsequent interpretation of thesegments. The formation of homogenious regions allows for acharacterization by texture parameters besides backscatter coefficients.To avoid a subjective selection and characterization of trainingsegments two airborne line scanner systems, one for visible and theother for infrared digital images of the ice surface, are utilized forvalidation measurements. After the correction of the radiometric andgeometric distortion of the line scanners the image data are classifiedin a two-dimensional feature space. After the co-location of the linescanner images with the segmented SAR data it is possible to derivethe characteristics of different ice types from the radar signatures.