Aims: The effectiveness of the local treatment of experimental osteomyelitis caused by MRSA (Methicillin Resistant Staph. aureus) performed with the implantation of acrylic bone cement (PMMA) mixture plus 4% grepaßoxacin into the femur of rabbits. Methods: 36 rabbits with chronic MRSA osteomyelitis of the right femur (Norden Model) were treated with a new local grepaßoxacin delivery system prepared by a mixture of PMMA plus 4% grepaßoxacin. Osteomyelitis was introduced by inoculating of the MRSA and the placement of a needle serving as a foreign body. The follow-up of the infection was performed by clinical, microbiological and x-rays þndings. On the 3rd week all animals were reoperated and the needle was removed followed by implantation of the mixture. One control and þve treated animals were sacriþced each week thereafter until the 6th week. Results: Osteomyelitis was induced in all rabbits. The in vitro grepaßoxacin levels were high for 6 weeks at least. Concerning the histological þndings serious tissue reactions were not observed. The lesions and the bone structure are progressively rehabilated after the implantation. The biomechanical study didnñt inßuence the mechanical properties of bone cement due to grepaßoxacin. Conclusions: The above mixture could be an approved supplementary method for the treatment of bone infections. In the chronic osteomyelitis itñs possible to replace the gentamycin PMMA beads. Furthermore could be use as a spacer in loosen arthroplasties due infection in combination with antibiotic administration.