An array of fibrinolysis tests was applied to the plasmas of 125 untreated patients with breast carcinoma and malignant melanoma, localized or spread to regional lymph nodes with no detectable distant metastases, to see whether or not there may be changes related to the type or to the stage of malignancy. Breast carcinoma (a mucin secreting tumor) and melanoma (a neuroectodermal tumor) were chosen as examples of tumors that can be accurately staged for localization or spread. Forty healthy subjects matched for age served as controls. The most marked differences between malignant tumors and controls were elevated plasma levels of tissue plasminogen activator antigen (P less than 0.005), plasminogen activator inhibitor (P less than 0.01), cross-linked fibrin degradation products (P less than 0.001), fragment B beta 15-42 (P less than 0.001) and histidine-rich glycoprotein (P less than 0.005). For no fibrinolysis test were results significantly different between patients with localized and spread tumors. Our data indicate that in these tumors fibrinolytic alterations are an early phenomenon unrelated to spreading.