One hundred two women admitted for evaluation of an adnexal mass were tested prior to surgery by the computerized tube leukocyte adherence inhibition (LAI) assay. The test was positive in 24/35 (69%) patients, diagnosed after surgery as epithelial ovarian cancer while 50/67 (75%) of those diagnosed as benign masses were negative. Only 2/38 (5%) of normal control subjects showed a false-positive result. The LAI test described in this report showed a sensitivity of 88% and a specificity of 75% in stage I ovarian cancer; thus it may be useful for early diagnosis of ovarian malignancy.