Objective: This study was conducted to determine the impact of Type 1 diabetes mellitus and related factors on children and families. Methods: The descriptive study was conducted with the parents of 175 children aged 6-18 years with Type 1 diabetes mellitus. The data were collected using the "Child and Family Information Form" and the "Diabetes Family Impact Scale (DFIS)." pResults:It was determined that the parents' total median DFIS score was 21.42 (9.52-35.71) and the highest median score was 33.33 (11.11-66.66) in the "finances" sub-dimension score. There was a significant difference between the child's school success and the parents' "school" sub-dimension median scores, the mother's employment status and the "work" sub-dimension median scores, and the family's income level and the DFIS total median scores (pConclusions and Recommendations:It was concluded that diabetes mostly adversely affected the family in terms of "finances." It was also determined that the negative impact of diabetes on the family was higher in children with poor school success and in families where mothers were unemployed and whose income was less than their expenses. The negative impact of diabetes on the family increased as the ages of the child, mother, and father and the duration of diagnosis decreased and the HbA1c level increased. In line with the research findings, one should be aware of the factors (child's age, child's school success, parental age, parental employment status, family income level, duration of diagnosis, HbA1c level) that affect the negative effects of diabetes on the family. In addition, it is recommended to plan and implement the necessary initiatives to prevent the negative effects of diabetes on the family (especially in the financial field) since the child's diagnosis of diabetes.