Purpose: Few prospective studies have assessed anthracycline-associated cardiotoxicity in patients with sarcoma. We evaluated cardiotoxicity in patients with soft-tissue sarcomas administered doxorubicin in the phase III ANNOUNCE trial (NCT02451943). Patients and Methods: Patients were anthracycline-na€ive adults with locally advanced or metastatic disease and left ventricular ejection fraction (LVEF) ≥50%. Patients could receive eight cycles of doxorubicin at 75 mg/m2. The cardioprotectant, dexrazoxane, was allowed at investigator discretion. Symptomatic cardiac adverse events (AEs) were recorded using Medical Dictionary for Regulatory Activities and graded using Common Terminology Criteria for Adverse Events 4.0. LVEF deterioration was measured by echocardiogram or multigated acquisition scan, defined as a decrease to <50%, or decrease from baseline value >10%. Results: A total of 504 patients received ≥1 cycles of doxorubicin [median cumulative dose, 450.3 mg/m2 (range, 72.3–634.0)]. Median follow-up of cardiac AEs was 28 weeks. Dexrazoxane was coadministered more frequently to patients receiving higher cumulative doxorubicin doses (38.6% receiving <450 mg/m2, 88.5% receiving 450–<600 mg/m2, and 90% receiving ≥600 mg/m2) and did not affect treatment efficacy. LVEF deterioration was seen in 62 of 153 (40.5%) patients who received a cumulative dose <450 mg/m2, 82 of 159 patients (51.6%) who received 450–<600 mg/m2, and 50 of 89 patients (56.2%) who received ≥600 mg/m2. Grade ≥3 cardiac dysfunction occurred in 2% of patients at <450 mg/m2, 3% at 450–<600 mg/m2, and 1.1% at ≥600 mg/m2. Incidence of treatment-related cardiac AEs was low across all dose ranges. Conclusions: Although follow-up was short, these results suggest doxorubicin can be administered at high cumulative doses (>450 mg/m2), with a low rate of cardiotoxicities, in the context of dexrazoxane coadministration.