Approximately 30% of patients with diffuse large B cell lymphoma (DLBCL) will develop relapsed or treatment refractory disease following primary chemotherapy. Patients unable to undergo aggressive chemotherapy and stem cell transplant or CAR T-cell therapy have limited treatment options. Obinutuzumab, a type II CD-20 directed antibody, has been previously shown to have efficacy in these patients, though overall outcomes remain poor. Here, we investigated the safety and efficacy of combining obinutuzumab with cytoreductive radiation to all areas of disease in patients with relapsed DLBCL. A retrospective review of patients with treatment refractory DLBCL was performed. All patients were treated with external beam radiation to all sites of refractory disease with concurrent and adjuvant obinutuzumab. Patients were treated with obinutuzumab 1600 mg on days 1 and 8 of cycle 1, followed by 800 mg on day 1 for 8 total cycles or until progression. Toxicities were evaluated based on Common Terminology Criteria for Adverse Events (CTCAE) v5.0 criteria. Kaplan Meier analysis was utilized to calculate progression free survival (PFS) and overall survival (OS). Between 2016 and 2022, 8 patients with refractory DLBCL were treated with concurrent radiation and obinutuzumab. The median age at time of treatment was 70. The most common radiation dose was 50 Gy in 25 fractions (range 37.5 - 50 Gy). No grade 3 or greater treatment related toxicity was observed. The median number of prior lymphoma treatments was 2 (range 1-5). Fifty percent of patients had a complete response at the irradiated site, and no patients progressed at the site of radiation. Median PFS and OS were 30 months, with two patients dying of unrelated disease without recurrence at 30 and 60 months. Four patients did not develop evidence of recurrence with only one patient receiving additional therapy (planned CAR-T following radiation completion). In this small cohort of treatment refractory DLBCL patients, the combination of radiation and obinutuzumab was well tolerated without excessive treatment related toxicity. The combination resulted in durable disease control with prolonged overall survival without additional treatment in a subset of patients. Larger studies of this combination therapy in refractory DLBCL are warranted as bridging or definitive treatment.