The effect of sodium and stannous fluoride compounds on the coherence of Streptococcus mutans was examined. Both commercial and reagent grade preparations were tested on S. mutans, strain 6715. Test fluoride aliquots at various concentrations were added to sucrose suspensions of S. mutans at a starting microbial suspensions equivalent to 25% transmission as read in a spectrophotometer. Test samples were rotated at 35 degrees, 80 rpm in an incubated orbital shaker. Analysis at 560 nm at various time periods, was performed to determine increases in %T as a function of aggregate formation. SnF2 preparations routinely inhibited coherence at concentrations as low as .001%, whereas NaF showed no effects on microbial cell-to-cell coherence.