Background: Clonal expansion of CD4+ CD28- T cells is a characteristic finding in patients with rheumatoid arthritis. CD4+ CD28- T cells are oligoclonal lymphocytes that are rare in healthy individuals, but are found in high percentage in patients with rheumatoid arthritis. The presence of significant numbers of CD4+ CD28- T cells could shift the immune response from B-cells activation and production of immunoglobulins toward activation of type-1 T helper cells and production of IFN-γ and involvement of macrophages releasing matrix-degrading proteases. Patients with rheumatoid arthritis are at increased risk for multi-vessel CAD due to expansion of CD4+ CD28- T cells in those patients, as it contribute to the progression of atherosclerosis. Aim of work: We hypothesized that the expansion of unusual T lymphocytes, CD4+CD28- T cells, might represent a key pathogenic mechanism of CAD in rheumatic patients.Methodology: flowcytometric detection of expansion CD4+ CD28- T cells was conducted on 42 cases with rheumatoid arthritis, who were selected from Rheumatology Clinic of Kasr Al-Ainy Hospital, Cairo University.Result: The CD4+CD28-T-cell frequency was higher in rheumatic patients with EAM than both, patients with no EAM and the control group.Conclusion: Expansion CD4+ CD28- T cells are strongly associated with occurrence of CAD in rheumatic patients.