In the present investigation we examined the effect of three brands of coffee on microbial volatile sulfur compound (VSC) production using a decarboxylase incubation assay. Stimulated whole saliva was added to decarboxylase medium supplemented with 0.005% hemin. Incubation was carried out anaerobically for 72 h in the presence of powdered coffee at concentrations ranging from 0.5 to 2.0% (w/v), as compared with appropriate controls. VSC levels were determined using OralChroma™ and Halimeter™ and malodor was scored by an experienced odor judge. Experimental biofilm was grown with or without coffee and examined for VSC-producing bacteria using confocal laser scanning microscopy. Results showed that VSC and malodor levels were decreased by 85% in the presence of 2% coffee. The data suggest that coffee components reduce malodor production, VSC levels and experimental biofilm VSC-producing bacteria in vitro.