This study and inventory of active rock glaciers was carried out by means of the usual techniques used in the study of alpine permafrost. First, the rock glaciers were located by means of aerial photography and field work. Second, a detailed geomorphological map was prepared, to detect the active processes in each rock glacier. This includes geotransect and surface analysis (clast roundness, clast forms, particle orientation and lichenometric measurements). Third, complementary measurements (water temperature and BTS [bottom temperature of snow] measurements) were carried out. These three studies allowed us to determine the activity or inactivity of previously detailed landforms, and to classify them as active, inactive, or relict rock glaciers. The external landforms, frontal slope, vertical organization, flow forms, absence of lichens and the descriptive parameters of rock glaciers allowed us to classify them as relict or active ones. On the Besiberri, Gemelos, and Argualas rock glaciers we have carried out photogrammetric studies, and on the Argualas rock glacier we carried out a topographic survey from 1991 and also geoelectric soundings (San Jose et al. 1992; Serrano et al. 1995; Fabre et al. 1995). These data are presented on the CAPS Version 1.0 CD-ROM, June 1998.