The review discusses physicochemical treatment of wastes, in particular those exhibiting toxic character, leading to the prevention of noxious substances to be leeched into environmental media. Further a survey is presented of various types of building agents and of solidification technologies serving to the immobilization of wastes before their permanent storing in the dumps, or if need be, their use as building materials. For evaluating the properties of products resulting from these treatments a number of tests is used enabling an assessment of the efficiency of the above processes and some instrumental methods serving for the elucidation of their internal structure if necessary.