To study IgG antibody persistence and temporal change in SARS coronavirus (SARS-CoV) infected patients, 22 patients recovered from SARS in Beijing were recruited and followed-up from 2004 to 2008, serum samples from patients were collected every year. We checked and analyzed the SARS-CoV IgG antibody (Ab) for five consecutive years using the commercial ELISA test kit. The results showed that: all of the serum were SARS-IgG antibody-positive the first year after recovery, the titer of most serum remained at high levels at the 2ed and 3rd year post infection. The Ab titers significantly declined at 4th year post infection. The IgG Ab was almost undetectable after 5 years post infection. In conclusion, SARS-CoV IgG Ab can be maintained for more than 3 years post infection, however, the titer of IgG Ab has declined markedly 4 years later. These data provide a useful reference for diagnosis and control of SARS infection, the evaluation of immune response and vaccine efficacy.