Background: New treatment methods for cardiovascular and autoimmune illnesses take advantage of (IL-27) pro- and anti-inflammatory properties. Objective: To assess the level of IL-27 level and echocardiographic parameters in children, and adolescents with type 1 diabetes mellitus (T1DM). Patients and Methods: at Department of Pediatrics, Diabetes Outpatient and Echocardiography Cardiology Unit, Zagazig University Hospitals, we conducted this case-control study on 30 children diagnosed with T1DM and 30 healthy age- and sex-matched subjects who were selected as non-diabetic group (controls). Serum lipid and IL-27 measurements in addition to echocardiography were done. Results: There was significant higher value of following echocardiography measures: LVIDs, LVIDd, LVId, LVIsd, PWD S, PWD D, RWT, LVMI, LVM both of bad and good control diabetic children compared to healthy control. While there was no significant difference regarding EF and FS between studied groups. There was significant higher value of serum interleukin 27 of bad control diabetic children compared to both; good control diabetic children and healthy children. But there was no significant difference, of good control diabetes children and healthy control children regarding serum interleukin 27. There was significant positive relation between serum interleukin 27 and disease duration of bad control type1 diabetic children. Conclusion: T1DM is connected with rise of IL-27 levels and lipid profile. This link is particularly evident in poorly managed patients demonstrating a relevant involvement of IL- 27 and dyslipidemia on the etiology of the condition