The recent emergence of coronavirus disease 2019 (COVID-19) pandemic has reassessed the usefulness of historic convalescent plasma transfusion (CPT). This review was conducted to evaluate the effectiveness of CPT therapy in COVID-19 patients based on the publications reported till date. To our knowledge, this is the first systematic review on convalescent plasma on clinically relevant outcomes in individuals with COVID-19. PubMed, EMBASE, and Medline databases were searched upto 19 April 2020. All records were screened as per the protocol eligibility criteria. We included five studies reporting CPT to COVID-19 patients. The main findings from available data are as follows: (a) Convalescent plasma may reduce mortality in critically ill patients, (b) Increase in neutralizing antibody titers and disappearance of SARS-CoV-2 RNA was observed in almost all the patients after CPT therapy, and (c) Beneficial effect on clinical symptoms after administration of convalescent plasma. Based on the limited scientific data, CPT therapy in COVID-19 patients appears safe, clinically effective, and reduces mortality. Well-designed large multicenter clinical trial studies should be conducted urgently to establish the efficacy of CPT to COVID-19 patients.