Introduction: Type 1 diabetes mellitus is one of the most common endocrine-metabolic disorders of childhood and adolescence and requires a continuous and rigorous therapeutic approach, with recognized impact on children and adolescents’ quality of life. The purpose of this study was to evaluate the quality of life of adolescents with type 1 diabetes mellitus and its relationship with clinical and laboratory aspects and lifestyle. Material and Methods: DQOL questionnaire was applied to type 1 diabetes mellitus adolescents managed at the Pediatric Diabetology consultation of a level II hospital for more than one year. Questionnaire has a global score between 36 and 180, with higher scores reflecting worse quality of life. Statistical analysis was performed in SPSS®. Results: Seventy-one percent (n=36) of adolescents responded to the survey, 55.6% of which male, with a median age of 15 years. Median DQOL global score was 66. Adolescents with good metabolic control had a median global score of 49, compared with 71 in adolescents with poor metabolic control (p=0.007). The median global score of self-perception of better health was 51 compared to 73 for self-perception of poorer health (p=0.007). Discussion: In general, adolescents in this study revealed a satisfactory quality of life. Adolescents with better metabolic control have a higher satisfaction and better quality of life. Adolescents with better self-perceived health have a better quality of life. Conclusion: Recognizing factors that affect quality of life of adolescents with type 1 diabetes mellitus is crucial to devise therapeutic strategies that meet their expectations, promoting treatment adherence and better metabolic control.