Phages for coagulase-negative staphylococci were adsorbed to heat-killed cells. The phages showed equal affinities for all the cells, which appeared to have an equal number of binding sites for all the phages tested. This number is estimated at 1.2 x 10(6) sites/cell. Competition for binding sites could be demonstrated between a pair of phages. It is concluded that coagulase-negative staphylococci have only a single series of binding sites for phage, probably the outer 20% or so of the wall teichoic acids. These organisms therefore bind all 'coagulase-negative' phages whether or not they are sensitive to them.