Abstract : Lupus nephritis (LN) is one of the main determinants of poor prognosis in patients with systemic lupus erythematosus (SLE), a multisystem inflammatory autoimmune disease. Several urine biomarkers have been identified that show a lot of promise for making clinical and laboratory tests for LN more accurate. The transforming growth factor -1 (TGF-1) is a cytokine that has become a key factor in the development of autoimmune diseases, such as SLE. Assess the role of urinary Transforming Growth factor β (TGF-β) in prediction of active lupus nephritis (LN) and to correlate its level with disease activity and renal status after six month of induction therapy. The current cross-sectional study included 41 SLE patients (19 cases without LN and 22 cases with LN) In addition to 20 healthy control group. All of the subjects in all of the groups were subjected to a full history, a full clinical exam, and routine laboratory tests. The Systemic Lupus Erythematosus Disease Activity index (SLEDAI) was utilized to evaluate the severity of the disease. To confirm the diagnosis and conduct an analysis of activity and chronicity indices, renal biopsies were performed on all the patients who met the LN ACR criteria. SLE cases showed significantly higher urinary TGF-β level 356.1 (53.2-476.8) when compared to control group 84.9 (37.1-156.4) (p<0.001). Moreover, cases with LN showed significantly higher urinary TGF-β level 402.3 (176.4-476.8) when compared to those without LN 270.1 (53.2-442.4) (p=0.005). Urinary TGF-β level decreased significantly after treatment in LN cases, (p<0.001). Higher urinary TGF-β level was considered as risk predictor for LN development among SLE cases. Urinary TGF-β could be used as sensitive non-invasive biomarker for differentiating healthy control from cases with SLE in addition to differentiating between SLE with and without LN with reasonable degree of sensitivity, specificity and accuracy. Furthermore, urinary TGF-β level was associated with response to treatment.