Covid-19 in immunocompromised patients shows a prolonged course and may lead to a poor prognosis. Although data on hyperimmune plasma for treatment of Covid-19 suggest an improved outcome in immunocompetent patients, limited data are currently available in immunocompromised patients. We present the case of a 62-year-old Caucasian woman, who was previously treated with obinutuzumab and bendamustine for follicular lymphoma and showed a prolonged positive test for Covid-19. Since no improvement was observed with standard of care (including remdesivir), the possibility of hyperimmune plasma infusion was discussed. A first dose of hyperimmune plasma was administered, with subsequent onset of fever, increasing inflammatory indexes and worsening radiological findings. Three days later a second dose of plasma was administered. Within twelve hours cough and fever disappeared, and oxygen at rest was discontinued. The patient was discharged 5 days later, and nasopharyngeal swabs resulted negative 16 days after discharge.