The second E. C. Workshop on Ultrasonic Tissue Characterization was organized for the assessment of research goals and plans as the basis to a grant proposal for a "Concerted Action" which will be forwarded to the European Commission. It should, therefore, not only be considered as a work in progress exhibition which succeeded the former activities within the E. C. (Inventory on Tissue Characterization in Europe and first Workshop). The Steering Group invited a 1 imited group of Institutes to send its group leader and a research fel low in the entitled field, who should expose the overall research program, as wei 1 as the more specific work on tissue characterization by RF signal analysis and spectroscopy. The ultimate goal of the Workshop has been the formulation of schemes of interaction among the Institutes and individuals and the definition of cooperative research programs. The remainder of the groups and some of the groups present are working in the field of analysis and processing of cl inical A- and B-mode echograms (i. e. video signals). Because this work is more closely related to the cl inical diagnostics it was decided that for that reason no preparatory workshop was needed. In the final proposal for the Concerted Action this work wi 1 1 get ample attention. Although not many clinicians were present, their positive interest in the sophisticated analysis techniques and their contribution to the dis cussions again have been a most valuable and stimulating experience.