Peripheral blood samples for the measurement of DD and CA 125 were drawn from 39 patients with ovarian cancer at different times from first surgery. Both median DD and CA 125 levels were significantly higher in the 20 samples drawn from patients with clinically evident disease than in the 37 samples from patients without clinical evidence of disease (477 vs 300 ng/ml p = 0.006, and 66 vs 11 U/ml, p < 0.0001, respectively). DD levels did not correlate with CA 125 levels. The sensitivity, specificity and diagnostic accuracy of the tests in the assessment of clinical disease status were as follows: 65%, 62% and 63% for DD (cut-off = 416 ng/ml); 70%, 92% and 84% for CA 125 (cut-off = 35 U/ml); 90%, 59% and 70% for DD "or" CA 125; and 45%, 95% and 77% for DD "and" CA 125. DD levels correlated with the clinical course of disease in ovarian cancer patients. However, the concomitant determination of DD and CA 125 did not improve the reliability of CA 125 assay alone in the follow-up of these patients.