We report the effect of staphylococci on induction of proteoglycan release from cartilage in organ culture and document the presence of a staphylococcal proteoglycan-releasing factor in the bacterial growth medium. Staphylococci cocultured with cartilage increased release of proteoglycan 3-4-fold within 48 hours. Viable cartilage was essential for maximum loss of proteoglycan. Killed bacteria had no effect on proteoglycan release. Four Staphylococcus aureus strains yielded growth media preparations active in proteoglycan release. Analysis of the proteoglycan subunits released from cartilage showed only limited degradation, and glycosaminoglycan chain length was not significantly altered.