Background: - more specific, sensitive, and in the same time non-invasive indicators for the early prediction of juvenile SLE are required. Aim: - to evaluate serum fractalkine (CX3CL1) as a diagnostic marker, predictor of nephritis, and indicator of disease activity in pediatric SLE. Methods: - study included 41 children newly diagnosed with SLE, age ranged from 5 to 18 years, 24 (58.5%) were presented lupus nephritis “diagnosed by renal biopsy”. A total of 20 healthy age and sex matched children were included as controls. Serum Fractalkine levels were measured using human CX3CL1 ELISA. Results: - Serum Fractalkine were significantly higher in SLE patients (median = 1323, range 591- 16547 IU/ml) than healthy controls (median = 950, range 591- 1583 u/ml) p=0.001. Serum Fkn can be a significant diagnostic marker for juvenile lupus indicated by the are under the ROC curve, AUC = 0.81 (95% confidence interval [CI], 0.70-0.92, P<0.001), at the level 1213 IU/ml serum Fkn detected SLE with sensitivity 0.78 (95% CI, 0.62 - 0.89), specificity 0.91 (95% CI, 0.71 – 0.99), positive predictive value 0.94 (95% CI, 0.80 – 0.98), negative predictive value 0.67 (95% CI, 0.55- 0.80), and accuracy 0.82 (95% CI, 0.71 – 0.91). Serum levels of Fkn showed no statistically significant differences when compared in patients with lupus nephritis against patients without nephritis, and was not correlated with disease activity. Conclusions: - Serum level of Fractalkine can be a diagnostic marker for childhood onset SLE either with or without lupus nephritis, with no significant correlation with activity status or the stage of LN.