Objective: Renal biopsy is the “gold standard” to determine renal activity in systemic lupus erythematosus (SLE), but it is expensive, invasive, and carries risk. Monocyte chemoattractant protein-1 (MCP-1), a chemotactic cytokine involved in the progression of glomerular and tubulointerstitial injury. We investigated urinary MCP-1(u MCP-1) as potential biomarker for lupus nephritis. Patients and methods: In 73 SLE patients, and in 23 healthy volunteers, urinary levels of MCP-1 were measured. Disease activity was assessed by total SLE disease activity index (tSLEDAI), and renal activity by renal SLE disease activity index (rSLEDAI), and both were correlated with uMCP-1. Sensitivity, specificity, and predictive values of MCP-1 to predict lupus nephritis (LN) were also calculated. Results: Significantly higher levels of uMCP-1 were observed in SLE patients with LN compared with those without LN, (MCP-1 P<0.001). Other significantly higher levels were observed in SLE patients with LN compared to control subjects (MCP-1, P<0.001). Positive correlations were observed between rSLEDAI and MCP-1 (r=0.635, p<0.001). Conclusion: The lack of availability of urine biomarkers has impeded development of new therapies for LN. Urinary levels of MCP-1 positively correlate with renal involvement as assessed by rSLEDAI with reasonable sensitivity, specificity and predictive values to detect LN.