Aim of Study: This work aims to determine serum and synovial levels of the granulocyte colony stimulating factor (G-CSF) in order to evaluate their utility as biomarkers of disease activity and/or severity in rheumatoid arthritis (RA) patients.Methods: Thirty patients with established RA as well as a control group of 20 apparently healthy individuals matched for age and sex to our patients were included and thoroughly examined.RA disease activity was assessed using the modified disease activity score of 28 joint count (DAS28)while, disease severity was evaluated using the clinical spread severityIndex (SSI).Plain radiography was done for both knees as well as affected jointswith evaluation according to Laresn scores.Serum and synovial levels of (G-CSF) were measured bythe ELISA technique.Conclusion: Our results reveal that G-CSF has a potential role in driving joint inflammationand also underscorethat G-CSF would likelyatherapeutic target in RA.