Objective Our aim in the present study was to elucidate how type 1 diabetes mellitus (T1DM) and sleep parameters interact, which was rarely evaluated up to the moment. Materials and methods Eighteen T1DM subjects without chronic complications, and 9 control subjects, matched for age and BMI, were studied. The following instruments used to evaluate sleep: the Epworth Sleepiness Scale, sleep diaries, actimeters, and polysomnography in a Sleep Lab. Glycemic control in T1DM individuals was evaluated through: A1C, home fingertip glucometer for 10 days (concomitant with the sleep diary and actimeter), and CGM or concomitant with continuous glucose monitoring (during the polysomnography night). Results Comparing with the control group, individuals with diabetes presented more pronounced sleep extension from weekdays to weekends than control subjects (p = 0.0303). Among T1DM, glycemic variability (SD) was positively correlated with sleep latency (r = 0.6525, p = 0.0033); full awakening index and arousal index were positively correlated with A1C (r = 0.6544, p = 0.0081; and r = 0.5680, p = 0.0272, respectively); and mean glycemia values were negatively correlated with sleep quality in T1DM individuals with better glycemic control (mean glycemia < 154 mg/dL). Conclusion Our results support the hypothesis of an interaction between sleep parameters and T1DM, where the glycemic control plays an important role. More studies are needed to unveil the mechanisms behind this interaction, which may allow, in the future, clinicians and educators to consider sleep in the effort of regulating glycemic control. Arch Endocrinol Metab. 2015;59(1):71-8.