Thirty-one patients with either advanced AML (18) or blastic CML (13) were treated with an intensive timed sequential combination of VP-16 (100 mg/m2/day i.v., days 1-3 and 8-10), intermediate-dose Ara-C (500 mg/m2 i.v. over 1 h q 12 h, days 1-3 and 8-10) and carboplatin (150 mg/m2/day i.v. continuous infusion, days 1-3 and 8-10). CR rates were 9/18 (50%) for patients with AML and 9/13 (69%) for those with blastic CML, for an overall CR rate of 58%. Among patients with AML, CR rates for specific subgroups were: primary resistant disease 2/6; resistant relapse 1/5; second relapse 6/7. Ten patients were refractory to VAC and three (10%) died of complications during marrow hypoplasia. Median overall survival was 7 months, and median DFS of the 18 responders 4 months. The major toxicity was myelosuppression and infection. The VAC regimen has significant activity and acceptable toxicity in myelogenous leukemias. The very high response rate observed in blastic CML warrants further testing of carboplatin-based regimens in this poor-risk form of leukemia.