Aim of the work: was to determine the level of IL-27 in patients with immune thrombocytopenia and its relationship to demographic,clinical and laboratory characteristics of patients as well as disease chronicity and response to treatment. Methods: A case control study carried out in Pediatric Hematology outpatient clinic , Zagazig University Hospitals. It included 80 subjects were divided into 4 group 1 included 20 patients with denovo ITP, group 2 included 20 patients with chronic ITP, group 3 included 20 patients with complete remission after 1st line therapy and group 4 (control group) included 20 healthy children as a control group. Results: there is significant difference regarding WBCs and Platelets, there was no significant difference in patients with ITP as regards hemoglobin level. ITP patients had significantly higher levels of IL-27 than controls. patients with acute ITP had the highest levels of IL-27 among patient groups ,while, patients in remission had the lowest IL-27 levels among patient groups. There was significant relationship between 1st line therapy and serum IL-27 in patients with ITP. Patients who received IVIG and combined steroids and IVIG had significantly higher IL-27 levels than others. There was significant relationship between 2nd line therapy and serum IL-27 in patients with chronic ITP. Where patients who received Eltrombopag had significantly lower IL-27 levels than others. Conclusion: we propose that the using of IL-27 as a predictor for ITP occurrence and for responsiveness to treatment but this need to be confirmed in larger studies.