Background/aim: The role of pro-inflammatory cytokines in the immunopathogenesis of idiopathic nephrotic syndrome had been widely postulated. Reports on the release of cytokines, during idiopathic nephrotic syndrome (INS) activation, were conflicting in defining a specific interleukin pattern during relapse and remission of the disease. The monocyte chemoattractant protein -1 (MCP-1) is a member of the CC chemokine family, and a potent chemotactic factor for monocytes. It plays an important role in the recruitment of monocytes/macrophages into renal tubulointerstitium .  Aim:The present study was designed to check urinary MCP-1 levels in pediatric patients with idiopathic nephrotic syndrome, and to detect effect of disease remission and activity on these levels. Patients and methods: the present work included fourty children with idiopathic nephrotic syndrome, subdivided into 2 groups: group A(cases in remission) & group B(cases in activity). Also twenty apparently healthy children age and sex matched with the cases have been included as a control group. All patients in this work  beside assessment of renal functions were clinically evaluated together with routine laboratory investigations. Levels of urinary monocyte chemotactic protein-1 were measured in the urine of patients during activity and remission of the disease. Urine samples from 20 age- and sex matched controls were checked for the same cytokine. Results: mean age for the studied cases were 8.14±2.50 years. In the present study, group (B) had the highest level of serum cholesterol and pr/cr ratio then group (A) and control group, the differences between the three groups were statistically significant. In contrast, group (B) had the lowest level of the serum albumin followed by group (A) then control group, again, the differences were statistically significant between the three groups. Also , the mean values of protein of 24 hours urine were significantly lower among group A than  group B, and the differences  between the two groups were statistically highly significant . this work show that Group (B) had the highest levels of uMCP-1 followed by group (A) then control group. The difference between the three group was statistically highly significant. Our work shows that 40% of cases in activity in group B were in relapse of NS and the remaining -60%- were in the 1^st attack of NS, and there was no significant difference between them regarding to uMCP-1. The current study shows that uMCP-1 level in group B and group A were highly positively correlated with Pr/Cr ratio ,Protein of 24 hours urine and serum cholesterol and highly negatively correlated with serum albumin. On the other hand uMCP-1 levels in control subjects were positively correlated with Pr/Cr ratio but not correlated with serum cholesterol or serum albumin. Conclusion: Our results support the role of monocyte chemotactic protein-1 in the pathogenesis of INS.