Diabetes in adolescence is a global public health issue that is getting more and more attention. It is a long-term metabolic condition defined by a partial or total lack of the hormone insulin. The key to effective control of diabetes is adherence to the complicated collection of chores that go into diabetic self-care practices. The adolescents spend (5-6) hours in school and during this time they are outside of parental care, so we need to monitor self-care practices of students with T1D. The aim of the study was to find out the relationship between self-care practices of secondary school students with type 1 diabetes mellitus and their sociodemographic data. Methods A descriptive (cross sectional) research design was used in this study. Sample size consist of (200) secondary school students. A non-probability (purposive) technique was used to collect data. Developed interview instrument was used in collect data. Data was gained in the al najaf center for diabetic and endocrine.