Cis-Dichlorodiammineplatinum(II) has shown good broad-spectrum activity in the current Division of Cancer Treatment (National Cancer Institute) tumor panel. It meets Decision Network criteria for activity in at least five of ten tumor systems (the ip B16 melanoma, the sc CD8F1 mammary carcinoma, the ip colon tumor 26, the ip L1210 leukemia, and the ip P388 leukemia). Activity against the sc colon tumor 38, the iv Lewis lung tumor, the ic ependymoblastoma, and the human breast tumor xenograft (MX-1) was marginal. No activity was detected against the human lung tumor xenograft (LX-1), but good, reproducible activity was observed against the murine M5076 ovarian carcinoma. No schedule-dependency was observed after ip administration against the ip L1210 leukemia. The recently developed subrenal capsule assay offers promise as a rapid way (less than or equal to 11 days) of ranking the sensitivity of a variety of human tumors to cis-dichlorodiammineplatinum(II) and other chemotherapeutic agents.