The fibrinolytic process was examined in cultures from malignant epithelial ovarian tumors and compared to normal ovarian tissue. The fibrinolytic enzymes, urokinase plasminogen activator (uPA) antigen and activity, tissue plasminogen activator (tPA) antigen and activity, plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2) antigen were measured in short-term primary cultures at weekly intervals over a 3-week period. The cultures comprised of 15 ovarian adenocarcinomas and 12 normal ovarian tissue samples. The concentration of uPA antigen (p < 0.01) and activity (p < 0.01) and (p < 0.05) levels were higher in malignant specimens on all 3 count days. Activity levels of tPA were elevated significantly in malignant specimens on days 7 and 21 (p < 0.05). No significant difference was found between PAI-1 levels. PAI-2 antigen levels were significantly higher in the tumor specimens on days 14 and 21 (P < 0.01). These data indicate that uPA may have a significant role in the biology of ovarian cancer and may be an important factor in early tumor spread. Further work is required on the effects of intervention in this biological process.