There is enhanced adherence of Staphylococcus aureus to HeLa cells if the organism is grown in the presence of sub-lethal concentration of aminoglycosides. In this study, we investigated the mechanism of this enhancement. Cell surface components obtained by lysosaphin digestion under hypertonic conditions were examined for binding to HeLa cells. The components considered responsible for the adherence were recovered more from aminoglycoside treated cells than from control, benzylpenicillin or chloramphenicol treated cells. Using a contact angle measurement, the bacterial cell surface was found to be more hydrophobic after growing in the presence of some aminoglycosides, and hydrophilic which decreased adherence, after growing in the presence of benzylpenicillin and ofloxacin. Spectinomycin and kasugamycin, which are both aminoglycosides which do not cause misreading, failed to enhance adherence suggesting that misreading caused by aminoglycosides plays an important role in the enhancement of adherence.