In a prospectively randomized study, 17 evaluable patients treated with adriamycin alone, 60 mg/m2 intravenously every 3 wk, were compared with 14 patients treated with adriamycin in the same dose and schedule plus streptozotocin. 500 mg/m2/day intravenously for 5 days every 3 wk. All patients had advanced sarcomas, but none had previously received either adriamycin or streptozotocin. Objective responses were seen in 9 patients on the single drug arm (4 with more than 50% tumor shrinkage and 5 with stabilization of disease), and in 8 patients given the combination drug arm (2 with more than 50% tumor shrinkage and 6 with stabilization of disease). Duration of response and survival from treatment for both treatment groups were similar. Transient hepatic dysfunction, renal function abnormalities, and nausea with vomiting were additive in the combination drug arm, the last two limiting therapy most. Leukopenia, thrombocytopenia, and mucositis appeared to be synergistically increased in patients receiving both adriamycin and streptozotocin. Patients with abnormal pretreatment renal function were able to tolerate the combination therapy without undue incidence of severity of renal toxicity. Patients who developed transient streptozotocin-related renal dysfunction were able to tolerate further doses of streptozotocin after their renal parameters normalized. Adriamycin in combination with streptozotocin did not offer any therapeutic advantage over adriamycin alone.