Staphylococcus aureus adhesion and osteoblast functions were assessed on functionalized poly(methyl methacrylate)-based terpolymers bearing randomly distributed carboxylate and sulfonate groups. These terpolymers were synthesized by radical polymerization, characterized by nuclear resonance spectroscopy and classified by the ratio R=[COO(-)/COO(-)+SO(3)(-)] in the range 0.5-0.8. Bacterial adhesion study showed that fibronectin-coated terpolymers with R varying from 0.5 to 0.8 exhibited inhibition rate of S. aureus adhesion from 90% to 98% as compared to the adhesion on unfunctionalized poly(methyl methacrylate). In contrast, the adhesion of osteoblasts onto the same functionalized terpolymers was decreased by 20% when compared to the results obtained on poly(methyl methacrylate). While the amount of attached osteoblasts are similar onto all the functionalized terpolymers whatever its R value, the cell proliferation was different and was found to vary with R in the range 0.5-0.8. Osteoblast proliferation, alkaline phosphatase activity and accumulation of calcium in the extracellular matrix of these cells, cultured on the functionalized terpolymers with R equal to 0.7-0.8 were similar to that observed onto non-functionalized poly(methyl methacrylate). In contrast, osteoblast proliferation was inhibited on terpolymers with an R value around 0.6. These results provide evidence that functionalized poly(methyl methacrylate)-based terpolymers with R ratio equaling 0.7-0.8 simultaneously inhibit bacteria adhesion and support osteoblast functions pertinent to new bone formation. These functionalized polymers could, therefore, be used as coating or grafted on orthopedic and dental implants to render them both bone compatible and able to prevent bacterial infection.