Background: The small joints of feet, hands and wrists are particularly vulnerable to impacts of Rheumatoid Arthritis (RA), the most prevalent auto-inflammatory disorder. The pathogenesis of RA is still unknown which leads to the on-going studies for further understands the pathogenesis and find new treatment targets. Galectin family includes Galectin-1 (Gal-1). It could be found in a large number of tissues with pro-inflammatory as well as anti-inflammatory effects relying on the cellular microenvironment. Objectives: The aim of the current study is to evaluate the relation between the disease activity of active rheumatoid cases under conventional medical treatment, and the level of Gal-1 in serum. Patient and methods: A total of 50 healthy controls and 50 RA patients; at least 18 years old using conventional medical treatment, were included in this case control study. Clinical evaluation, laboratory testing, serum Gal-1 levels, and evaluation of disease activity, was performed to all participants. Results: At a cutoff of >15 (ng/ml), the serum Gal-1 level in the RA group was significantly higher compared to the healthy control group. Serum Gal-1 was not significantly correlated with the activity of RA. Conclusion: Our results demonstrated the usefulness of measuring the serum levels of Galectin-1 in patients with RA with high validity. This proves the pro-inflammatory effect of Galectin-1 in RA patients.