The serum concentration of some enzymes, namely placental alkaline phosphatase, lactate dehydrogenase, 5′ nucleotidase and amylase, was determined by commercially available kit in 50 ovarian cancer patients and 31 patients with benign gynaecological disease before initiation of any treatment. The values were compared with those of 30 healthy women. Multivariate analysis showed a statistically significant difference between healthy women and ovarian cancer patients. These results indicate that by using discriminating function of the above four enzyme variables it is possible to sereen ovarian cancer in outpatient obsteric and gynaecological clinics (sensitivity 96%, specificity 83.3%, relative risk 11.7). Hence this system can serve as a suitable marker for ovarian cancer. © 1994.