Since the discovery of platinum compounds by Rosenberg, et al. in 1965 on the mitosis inhibitory action against Escherichia coli, the anticancer action of cis-diamminedichloroplatinum (II) (cisplatin) one of the platinum compounds, has called attention, and recently clinical trials of this compounds have been actively performed in the treatment of testicular and ovarian malignancies not only in the U.S.A. but also in Japan. We carried out a joint controlled trial of cisplatin (NK-801, Nippon Kayaku Co.) in the treatment of ovarian malignancies. The eligibility of the patients and evaluation of response were assessed according to the general response criteria proposed by Drs. Koyama and Saito. Fifty-seven patients were evaluable for the tumor response. Complete response were 11%, partial response 47%, and overall response rates 58% in ovarian malignancies, respectively. Toxicities were noted in the gastro-intestinal tract. Myelosupression and renal dysfunction were other prominent adverse effects.