[en] This report summarizes the results and conclusions of technical studies performed in ten laboratories of nine Member States. It includes brief descriptions of all waste forms studied during the past decade and discusses their major properties. The report focuses on the primary waste forms of interest and emphasizes the evaluation of leach performance, recognized as the single most important property of waste forms. Leach-test methods from laboratories of participating nations are described in some detail, followed by chapters addressing leach performance from several different perspectives. Factors having to do with solid waste form characteristics, such as thermal and radiation stability, are considered separately from leachant-related factors, such as the effect of flow rate or pH. There is some review of multicomponent systems tests which more accurately simulate repository conditions than have many earlier studies. A final chapter describes some ideas on near field-waste form release models which have developed during the last few years