Objective To investigate the possibility of transmission of severe acute respiratory syndrome (SARS) related coronavirus by transfusion of unreliable blood and relevant product. Methods ELISA technique was used to detect the antibodies of SARS associated coronavirus in the plasma from 158 volunteer blood donors, who were medical workers, before the SARS epidemic. The subjects with positive result were place under surveillance. Results There were two positive samples in 158 tested samples. The subjects with positive test result did not have the history of SARS infection. Conclusion There was no epidemic of SARS in the hospital. The transmission pathway of SARS was unknown. It seems that the risk of transmitting SARS by unreliable blood product transfusion is just a theoretical hypothesis. With further investigation of SARS, its transmission pathway will be hopefully made known.