S0515 was a phase 2 trial to determine whether the addition of bevacizumab to cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) plus rituximab (R-CHOP) would improve progression-free survival (PFS) without adding significant toxicity in patients with newly diagnosed advanced diffuse large B-cell lymphoma. A total of 73 patients were enrolled. For the 64 eligible patients, median age was 68 years, and 60% had International Prognostic Index scores more than or equal to 3. The observed 1- and 2-year PFS estimates were 77% and 69%, respectively. These PFS estimates were not statistically different from the expected PFS for this population if treated with R-CHOP alone. Grade 3 or higher toxicities were observed in 81% of patients, including 2 grade 5 events. The majority of serious toxicities were hematologic but also included 5 patients with gastrointestinal perforations, 4 patients with thrombotic events, and 11 patients who developed grade 2 or 3 left ventricular dysfunction. Higher baseline urine VEGF and plasma VCAM levels correlated with worse PFS and overall survival. In conclusion, the addition of bevacizumab to R-CHOP chemotherapy was not promising in terms of PFS and resulted in increased serious toxicities, especially cardiac and gastrointestinal perforations. This study is registered at www.clinicaltrials.gov as #NCT00121199.