Background: Immunotherapy with anti CD20 is often associated with mild easily manageable infusion reactions. In rare cases, patients experience severe drug hypersensitivity reactions (DHR) serum sickness or anaphylaxis. These in turn may lead to discontinuation of the drug. In our experience, switching to a different anti-CD20 agent is a feasible alternative to discontinuation or desensitization protocols. Methods: From our pharmacology database we identified all the patients that received rituximab and/or obinutuzumab, and/or ofatumumab, and/or all the patients who received a flat dose of less than 50 mL of the same drugs and were followed at our institution. From the medical record, we identified all the cases where the anti-CD20 antibody was changed due to allergy, serum sickness or other types of DHR, and all those who received minimal doses of anti-CD20 in the context of a desensitization protocol. DHRs were evaluated either by an allergist, or by retrospective review following the World Allergy Organization guidelines. Our primary comparison, was to assess the proportion of pts able to completed planned infusion of abs using either approach (Fisher’s exact Test). Results: Among 343 patients receiving at least two different anti-CD20 antibodies or a flat dose of < 50 mL, we identified 44 patients experiencing severe DHRs needing intervention. At the time of the reaction, 16 (36%) received the anti-CD20 as single agent, 24 (54%) in combination with chemotherapy, 4 (9%) in combination with ibrutinib or lenalidomide. In 9 (20%) patients the reaction was defined as anaphylactoid (8 rituximab; 1 obinutuzumab) and in 8 (18%) patients, all receiving rituximab, as serum sickness. Episodes of DHR were addressed with either desensitization (n = 29) or change of anti-CD20 agent (n = 25), 9 patients received both of these approaches, one patient switched anti-CD20 antibodies twice. Overall, 21 desensitizations were successful (72.4%), 8 failed; 23 changes of anti-CD20 were successful (92%) and 2 failed (p = 0.09). Conclusions: In patients with DHR use of an alternative anti-CD20 antibody is safe and is an alternative or complementary approach to anti-CD20 desensitization.