Silver halides represent a yet unexplored avenue for imparting antimicrobial activity to calcium phosphates. Negtively charged silver halide colloids (AgI, AgBr and AgCl) were added to synthesized amorphous calcium phosphate. Concurrent melting of silver halides and crystallization to carbonated apatite at 700 oC increased the silver halide surface area available to bacteria and formed a lower solubility apatite. The effect of the matrix solubility on antimicrobial response could then be investigated. Pseudomonas aeruginosa was more sensitive to silver iodide and silver bromide than Staphylococcus aureus. Silver iodide demonstrated greater activity than silver bromide. Silver chloride did not produce an antibacterial response. Both amorphous calcium phosphate and carbonated apatite displayed similar antibacterial activity when accompanied by silver halides. It is thought that amorphous calcium phosphate dissolves more readily and increases the bioavailability of the silver halide particles. Silver iodide displays a greater antibacterial response of all silver halides, with a response that is improved in a more resorbable matrix.