Vascular plasminogen activator levels were measured preoperatively in 66 women with gynecologic malignancies. These levels were compared to levels in a matched control group of 84 women and to the incidence of postoperative venous thromboembolic disease in the patient group. Significantly lower levels of plasminogen activator were measured in patients who developed thrombotic complications (p = 0.0014). When results were stratified according to tumor location, patients with ovarian carcinoma had significantly higher activator levels than those found in control subjects (p = 0.0072), and significantly lower levels were associated with endometrial malignancy (p = 0.0140). Measurement of releasable plasminogen activator before operation may be an effective, noninvasive means of identifying patients potentially at risk for venous thromboembolic disease. Postoperative measurement of plasminogen activator may eventually find a role in monitoring tumor therapy and recurrence.