Rheumatoid arthritis (RA) is one of the autoimmune diseases characterized by the synovial inflammation which causes organs and tissues damage especially synovial tissues and joints. The study included 50 serum samples from patients with rheumatoid arthritis (RA) when compared with 50 serum samples from healthy individuals as control with age range 35 – 60 years (41.3 ± 2.4 years vs. 41.0 ± 2.0 years, respectively). ELISA technique was used to assess the Anti-cyclic citrullinated peptide IgG antibody (anti-CCP IgG Ab) level, anti-rheumatoid factor IgG antibody (anti-RF IgG) and anti-Cytomegalovirus (anti-CMV IgG) antibodies frequencies in the studied groups. The present findings demonstrated that all RA patients have 100% seropositive frequencies for each anti-CCP IgG and anti-RF IgG antibodies compared to 100% seronegative frequency in controls. There was a significantly increased frequency and level of anti-CMV IgG antibody in RA patients compared to control. The present findings suggested that CMV may one of the triggering factors for RA in cooperation with the incidence of anti-CCP and anti-RF antibodies.