Human carcinoma cells cultured in serum free medium produced an enzyme present as two different isoforms of 62 and 59 kDa which was found to degrade hyaluronan and chondroitin sulfate, with optimum activity at pH 4.0 and 0.03 M NaCl. The activity was suppressed by treatment with 250 mM apigenin and 1 mM DTT. The one-dimensional and two-dimensional gel patterns of tumor hyaluronidase differed from those of human serum hyaluronidase. Deglycosylation of tumor hyaluronidase caused nearly complete elimination of activity, suggesting the importance of sugar chains in enzymatic function. The results of treatment with neuraminidase, in addition to the findings for the enzyme mentioned above, suggest hyaluronidase from carcinoma cells and serum hyaluronidase to differ in sugar chains and/or the core protein. Tumor hyaluronidase was shown to be endo-beta-N-acetyl-D-hexosaminidase and tetrasaccharide was identified as the major product, thus indicating the tumor hyaluronidase to be a testis-type hyaluronidase.