Mono- and biexponential killing curves for vancomycin over a 2- to 50-micrograms/ml concentration range were generated for 11 Staphylococcus aureus isolates and 12 coagulase-negative Staphylococcus species in the logarithmic phase of growth. Nonlinear least-squares regression of the initial growth rate and disappearance were not significantly different for lower or higher concentrations of vancomycin in broth.