Objectives: This study aims to investigate the relationship of hemoglobin level with disease activity in patients with rheumatoid arthritis (RA). Patients and methods: The hemoglobin level, the 66/68 joint count, the Disease Activity Score 28 joints (DA528), the Health Assessment Questionnaire (HAQ), the Visual Analog Scales (VAS), the Modified Sharp Score (MSS), and the disease duration in 89 patients with RA were used to analyze the possible relationship. The World Health Organization (WHO) criteria for anemia uses a hemoglobin threshold of < 120 g/L for women and <130 g/L for men. Pregnant or breastfeeding patients, patients with a history of other inflammatory or no inflammatory arthritis, malignancies, chronic infectious and inflammatory diseases and other diseases in the stage of decompensation were excluded from the study. Results: Anemia was observed in 64% of the patients (1st group); the other group (211d group) had normal levels of hemoglobin. There was a statistically significant negative correlation between hemoglobin level and swollen and tender joints' count, DA528, HAQ score, VAS, MSS, and disease duration (p <0.001). DA528, HAQscore, VAS, MSS, swollen and tenderjoints' count and disease duration were significantly (p <0.001) higher in 1st versus 2nd group. Conclusion: In conclusion, we determined that low hemoglobin level was significantly related to disability and impairment, disease activity, articular damage, pain and disease duration in RA patients in our study. We believe that by keeping disease activity under control, therefore preventing articular damage, the disability in RA patients can be lessened or possibly even eliminated. (c) 2014 Elsevier Editora Ltd a. All rights reserved.