Objective To review the association between chlamydia pneumoniae (CP) infection and cerebral infarction. Methods We electronically searched MEDLINE, BIOSIS, VIP database, and China Full Text Journal Database from Jan. 1990 through Dec. 2007 to identify case-control studies about the association of CP and cerebral infarction. The quality of the included studies was assessed and the RevMan 4.2 software was used for meta-analyses. Results A total of 22 studies were included. The results of meta-analyses showed: ① When the microimmunofluorescence (MIF) method was used to examine CP antibody in serum, the positive rate of the cerebral infarction group was higher than that of the control group when the positive infection was defined by IgA≥1?16 [n=8, OR=2.18, 95%CI (1.49 to 3.49), Plt;0.0001]; but when positive infection was defined by IgA≥1?32 (n=3), IgG≥1?32 (n=6), or IgG≥1?64 (n=5), there were no significant differences in the positive rate between the two groups [OR (95%CI) were 1.47 (0.97 to 2.24), 1.24 (0.82 to 1.86), and 1.23 (0.98 to 1.55), respectively]; ② When the ELISA method was used to examine CP-IgG antibody in serum, the positive rate of the cerebral infarction group was higher than that of the controlled group [n=8, OR=2.40, 95%CI (1.42 to 4.06), P=0.000 2]. ③ The acute and chronic CP infections were associated with the incidence of cerebral infarction [n=4, OR=7.22, 95%CI (2.68 to 19.49); n=4, OR=4.30, 95%CI (3.40 to 7.40)]. Conclusion ① The association between CP infection and cerebral infarction is determined by the positive criterion. IgA antibody is more sensitive than the IgG antibody. When the positive infection is determined by IgA≥1?16, CP infection is associated with cerebral infarction. ② The results of ELISA for examining CP-IgG support the association between CP infection and cerebral infarction. ③ Both acute and chronic CP infections are associated with cerebral infarction, but these associations needed to be proven by more scientific studies.