Background: Some evidence has shown a relationship between human cytomegalovirus (CMV) infection and pregnancy loss. However, whether recurrent or latent CMV infection or altered immune response to CMV is related to recurrent pregnancy loss (RPL) is unclear. We evaluated CMV infection and avidity of antibodies to CMV in women with RPL. Materials and Methods: This case-control study was conducted on 43 women with RPL referred to a clinical immunology out-patient clinic in Isfahan (Iran), and 43 age-matched multiparous women without history of abortion as control subjects. Patients and controls were evaluated for anti-CMV IgG and IgM antibodies and IgG avidity index (AI) using the enzyme linked immunosorbent assay method. Student′s t-test and Chi-square test were used to analyze the data. Results: One case (2.3%) of positive anti-CMV IgM was detected in each group. Anti-CMV IgG positivity was more frequent in patients than in controls (90.6% vs. 69.8%, P = 0.014), but there was no difference between the two groups in anti-CMV IgG AI (79.4 ± 11.4 vs. 80.1 ± 10.2, P = 0.781). IgG titer was significantly higher in seropositive cases with RPL than seropositive controls (5.18 ± 1.99 vs. 2.00 ± 0.81, P < 0.001). Conclusion: We found that previous exposure to CMV was significantly higher in patients with RPL than the control group. However, no association was found between IgG AI and RPL. Further investigations are needed to find whether latent CMV infection starts an indirect process of autoimmune etiology in RPL or women with RPL have recurrent or reactivation of CMV infection.