[en] The solidification of liquid radioactive waste materials creates difficulties if these contain organic substances such as, e.g., organic phosphoric acid esters, organophosphoric acids and their mixtures with hydrocarbons, or machine oils. It is proposed to process such an organic waste liquid with an organic solid into a homogeneous, soft, shapeless mass. This can easily be achieved by adding bitumen (about 50 wt.%) or synthetics such as polyethylene, polyvinyl chloride, polystyrol (about 20 wt.%), with heating if necessary. This organic mass is then brought into a suspension of a hydraulic binder in water (about 40 wt.% cement or gypsum) and dispersed; the whole mixture solidifies by the setting of the hydraulic binder to molded bodies. A weight ratio of organic mass to cement or calcium sulphate suspension of 1:2 and 1:3 is of advantage. The molded bodies enable an 'environmental', safe handling for transport and final storage. (orig./PW)