Background Lupus nephritis is one of the most serious manifestations of Systemic lupus erythematosus. Proteinuria, complement level, anti-dsDNA and creatinine are the most widely used to assess activity.   Aim of Work The aim of this study was to assess the relationship of urinary s CD25 with lupus nephritis activity as a noninvasive biomarker in children.   Patients and Methods The study was conducted on 30 patients divided into 2 groups; Group I: 20 patients of SLE, subdivided into 2 subgroups according to presence of lupus nephritis and Group II: 10 healthy subjects as a control group. Urinary sCD25 was measured in both groups.   Results Urinary sCD25 was significantly higher in active LN in comparison to inactive and controls. Urinary s CD25 level was correlated with SLE activity, proteinuria and blood urea.   Conclusion Urinary sCD25 is a useful noninvasive technique for assessment of lupus nephritis as it shows a good correlation with some clinical and laboratory parameters of disease relapse.