The invention relates to a polymethylmethacrylate bone cement composition that contains polymethylmethacrylate, radio-opaquer, methylmethacrylate and/or alkylmethacrylates, and an initiator system and comprises, in addition, ferromagnetic and/or superparamagnetic particles of a particle size of up to maximally 500 .mu.m--which allows it to be heated by alternating magnetic fields--and further contains at least one biodegradable or biocompatible crystalline substance having a melting point in the range of 43-46.degree. C. The cured cement can be used for local over-heating (hyperthermia) therapy in the absence of undesired temperature peaks.