Forty-nine patients with regionally confined recurrent malignancy were treated with intra-arterial cis-diamminedichloro platinum II in a Phase I-II trial. A safe starting dose of 120 mg/m2 was established. An overall response rate of 45% was noted with significant responses observed among patients with melanoma, sarcoma, breast carcinoma, and neuroblastoma. Side effects included transient renal and bone marrow toxicity as well as neurotoxicity and ototoxicity (6%), the latter usually with residual damage. The rational basis and advantages of treatment with intra-arterial cis-platinum are discussed.