Background: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by various immunological abnormalities, including dis-regulating activation B lymphocytes with subsequent productionof a large quantity of autoreactive-antibodies. It is also hypothesized that T helper-17 lymphocytes (TH-17) may have a role in this disease. The aim of the present work was to determine the role of TH-17cells expressing the retinoid acid related orphan receptor gamma t (RORγt) mRNA in the pathogenesis of SLE disease. Methodology: The study was conducted on 30 female SLE patients fulfilling SLICCA /ACR criteria for SLE classification and 30 healthy subjects sex- and age-matched apparently as control group with no previous history of autoimmune diseases. SLE Disease Activity Index was calculated for SLE patients. Level of expression of (RORγt) mRNA of IL-17 were measured in all patients and control by quantitative Real Time Polymerase chain reaction (Q PCR). Results: The mean ± SD of RORγt mRNA expression levels in SLE patients (3.6±6.1) was significantly reduced compared to that of controls (11.7±13.7) (p= 0.008).Neither the clinical features of SLE nor the laboratory parameters have significant relationship with RORγt expression. Conclusion: The reduction of RORγt mRNA expression in TH-17 lymphocytes may point out to the regulatory protective role of TH-17 in the pathogenesis of SLE. Agents that block the functions of these cells should be tried.