Because taurine may be a component of the capsular polysaccharide of the M strain of S. aureus, the uptake and metabolism of [1,2-14C]taurine was studied in a variety of encapsulated and unencapsulated S. aureus strains. Taurine was taken up by all strains studied. A discrepancy between uptake measured as depletion of radioactivity from growth medium and as cell-associated radioactivity suggested that taurine may be catabolized to CO2 in some strains. In most strains, cell-associated radioactivity was located mainly in cold trichloroacetic acid (TCA)-soluble (pool metabolites) fractions. About 90% of the cell-associated radioactivity was present in the pool metabolites fraction in the M strain, and .apprx. 10% in hot TCA-soluble (nucleic acid-teichoic acid-capsular polysaccharide) fraction. Radioactivity in spent medium and the capsular polysaccharide-containing fraction appeared to be present as taurine in this strain. Radioactivity in the pool metabolites fraction of 3 strains did not chromatograph as taurine, indicating that taurine was converted into other cell metabolites. One strain incorporated radioactivity from taurine into cellular macromolecules, thus revealing a heterogeneity of staphylococcal taurine metabolism.