Background The aim of this randomized, controlled trial is to determine whether antisevere acute respiratory syndrome coronavirus 2 hyperimmune globulin (COVIG) protects against severe coronavirus disease 2019 (COVID-19) in severely immunocompromised, hospitalized, COVID-19 patients. Methods Patients were randomly assigned to receive COVIG or intravenous immunoglobulin (IVIG) without SARS-CoV-2 antibodies. Results Severe COVID-19 was observed in 2 of 10 (20%) patients treated with COVIG compared to 7 of 8 (88%) in the IVIG control group (P = .015, Fisher’s exact test). Conclusions Antisevere acute respiratory syndrome coronavirus 2 hyperimmune globulin may be a valuable treatment in severely immunocompromised, hospitalized, COVID-19 patients and should be considered when no monoclonal antibody therapies are available.