Amplifications of myc oncogenes (c-myc, N-myc) were studied by Southern blot hybridization methods in ovarian cancers. Fourteen cases were primary ovarian cancers and one case was metastatic ovarian cancer. Primary and metastatic foci of three primary ovarian cancers were compared. A serous adenocarcinoma had a c-myc gene amplification more than 10 fold without N-myc gene amplification. This case also had an amplification in other c-myc probes with upper and down streams of the second exon. The results suggested that this case had c-myc gene expression. One of these cases had 5 fold amplification of the metastatic focus compared with the primary focus. The amplified c-myc gene did not show relations among clinical courses, prognosis and histologies.