Objective: the aim of this study is to determine the role of urinary and serum lipocalin-2 as a biomarker in the renal disease activity in systemic lupus erythematosus (SLE).Methods: thirty patients with SLE were divided and selected into fifteen patients with lupus nephritis (LN), and fifiteen SLE patients without LN.All patients were subjected to full history taking, full examination, complete urine analysis and detection of urinary/creatinine ratio (Upro/cre) and all the laboratory and radiological examination needed for SLE diagnosis. SLE Disease Activity Index (SLEDAI) and the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) score were evaluated to all SLE patients.Results were matched with fifiteen control participents with normal urine analysis, all were age and sex matched.Results: Urinary lipocalin-2 showed highly significant statisical difference in comparing all SLE patients and the controls (p<0.001).The LN group showed higher mean levels of urinary lipocalin-2 than the compared group (p<0.001). Urinary lipocalin-2 correlated significantly with Upro/cre, blood urea nitrogen, serun creatinine, total SLEDAI and the renal SLEDAI, also it correlated significantly with the SLICC score and the renal parameter of the SLICC score. No correlation was found between urinary lipocalin-2 and the extra-renal SLEDAI, disease duration, anti-dsDNA, C3 and C4. The levels of serum lipocalin-2 did not show significant statistical difference between all SLE patients and the control, and also no significant statistical difference between (LN) group, and the non-LN group. Also no correlation was found as regards the urinary and the serum lipocalin-2.Conclusion: Urinary lipocalin-2 could be used as a biomarker of SLE disease activity as well as severity. Serum lipocalin-2 did not prove its usage in the assessement of renal involvement in SLE.