IntroductionHemogram parameters have been recently proposed as markers of inflammation in various studies from different parts of the world. Two of these hemogram parameters are red cell distribution width (RDW) and mean platelet volume (MPV). AimTo evaluate the relation between RDW and MPV with disease activity of rheumatoid arthritis. To assess whether RDW and MPV can be used to follow disease activity in RA patients. MethodsThis is an observational cross-sectional study that was carried out on 60 rheumatoid arthritis patients who fulfilled the ACR/EULAR2010 classification criteria of RA attending to Rheumatology and Rehabilitation inpatient and outpatient clinics at Zagazig University Hospitals. All cases were subjected to full history taking, clinical examination, and laboratory investigations; differential complete blood picture (CBC), acute phase reactants (CRP and ESR), rheumatoid factor (RF) and anti-cyclic-citrullinated peptide (anti-CCP) antibodies. Disease activity was measured by disease activity score 28 (DAS28). ResultsThe cut-off levels of RDW and MPV were 14.85 and 11.25. Patients with RDW>14.85 had higher Disease Activity Score 28 (DAS28; p=0.0003), ESR (p=0.0001) and CRP (p=0.0001). RDW was positively correlated with disease activity markers (ESR, CRP and DAS28) in rheumatoid arthritis patients. But, DAS28 was not different between patients with MPV>11.25 and <11.25. ConclusionRDW was strongly correlated with disease activity. Also, RDW was better than ESR and CRP in detecting RA disease activity. According to these findings we suggest that RDW can be used in clinics to follow disease activity. In addition, RDW is widely available; as it's usually included in routine complete blood picture and there will be no need for further cost.