We evaluated a new immunoluminometric technique (ILMA) for the measurement of the cancer antigens, CA 19-9 and CA 125 in serum. A satisfactory reproducibility was found, coefficients of variation ranging from 4.2 to 7.3% in within-run and between-run assays. The linearity of tests was maintained over a wide concentration range. Mean analytical recovery was 94% for CA 19-9 and 98% for CA 125. A significant agreement between results obtained by immunoradiometric assays and evaluated methods was found both for CA 125 (ILMA = 0.917 IRMA + 1.048; r = 0.966; n = 98) and CA 19-9 (ILMA = 1.156 IRMA + 0.996; r = 0.995; n = 100).