UNLABELLED background: The aims of this study were to assess the prevalence of anti-mutated citrullinated vimentin (MCV) antibodies and rheumatoid factor (RF) and to evaluate their association in rheumatoid arthritis patients, both Saudi and non-Saudi. METHODS Retrospectively, we studied 280 rheumatoid arthritis patients, at King Abdulaziz University Hospital. The antibodies were measured by enzyme linked immunosorbent assay and rheumatoid factor by nephelometry. RESULTS The 280 patients included 196 Saudis and 84 non-Saudis, 88% females and 12% males, and the mean age was 45.3 years (SD = 14.3). Prevalence of rheumatoid factor was 141/280 (50%) divided as 93/196 (47.5%) Saudis and 48/84 (57%) non-Saudis, with no significant differences (p > 0.05). Prevalence of mutated citrullinated vimentin antibodies was 165/280 (58.2%) divided as 121/196 (61.7%) Saudis and 44/84 (52.4%) non-Saudis, with no significant differences (p > 0.05). Among RF -ve patients, considerable numbers were anti-MCV +ve, and vice versa. Also, among the anti-MCV -ve patients, considerable numbers were RF +ve, and vice versa. In all cohorts and in Saudi and non Saudi patients, anti-MCV positivity was significantly associated with RF positivity (odds ratio (OR) 3.15; 95% CI 1.9, 5.19/p = 0.000); ESR and CRP were high with significant correlation (p < 0.005) with each other, with RF positivity but not with anti-MC positivity. Anti-MC positivity showed no significant correlation with age and gender. CONCLUSIONS In this cohort of patients, anti-MCV antibodies are a useful diagnostic tool for RA, but its combination with RF is essential. Both markers are significantly associated. Larger scale studies are recommended. Correlation of anti-MCV with treatment and with disease activity still has to be published.