: a beam of light was thrown on IL-7 in the rheumatology community because of increased levels of expression in the RA synovium as well as the synovial Fluid. The tissue level of IL-7 is extremely accompanied by the local measures of RA activity; nevertheless, its circulating level remains controversial. Aim of the work: To evaluate the levels of serum IL-7 in RA cases and to compare it to disease activity. Also, to investigate IL7 as a biomarker for RA diagnosis. Patients and Methods: Serum samples from 50 RA cases and 50 age & sex-matched control subjects were tested for IL-7 via ELISA, and DAS28 was utilized for assessment of the disease activity in RA cases. Results: The patients’ mean age was 41.8 ± 12.1 y, mean disease duration was 6.5 ± 5.8 y and. The included cases were 44 women and 6 men. The mean DAS28 of cases was 3.95 ± 0.9. Serum levels of IL-7 were elevated in RA cases (105 ± 88.6 pg/ml) than in the control group (52.4 ± 35.6 pg./ml) (p < 0.001). Serum IL-7 levels showed significantly correlation with DAS28 (r = 39, p = 0.001). At a cutoff > 50 pg./ml, serum IL7 levels exhibited a sensitivity & specificity of 78% and 62% respectively (p < 0.001) in diagnosing RA. Conclusion: Serum IL-7 levels were elevated in RA cases compared to the control group and were elevated with higher disease activity rendering it a propitious biomarker for RA. IL7 proved a great diagnostic power for RA disease that could help to understand the pathogenesis of RA and determine novel treatment options.