Erythromycin and colistin demonstrate a non-antagonistic ability to inhibit the growth of a wide variety of aerobic and anaerobic bacterial isolates. When incorporated in Surgical Simplex P Radiopaque Bone Cement, fabricated cement pellets were effective in inhibiting 98% of all anaerobic and aerobic test isolates. Separate experiments indicate that each antibiotic can diffuse from polymerized cement, and that the concentration of each antibiotic is consistently above the minimum inhibitory concentration of 96% of the isolates. We conclude that erythromycin/colistin Surgical Simplex P radiopaque Bone Cement is a worthy candidate for clinical investigation.