Despite improvements in treatment regimens and technology, less than 20% of adults with type 1 diabetes (T1D) achieve glycemic targets. Sleep variability (variability in sleep duration) and insufficient sleep duration may adversely affect glycemic control, diabetes distress, and mood. This 8-week pilot RCT aimed to determine if a sleep intervention (Sleep Opt) would improve sleep variability and duration, glucose (A1C, time-in-range (TIR), glycemic variability), and patient-reported outcomes compared to an attention control intervention in adults with T1D. Methods: Eight T1D subjects with inadequate (sleep duration < 6.5 hr) or irregular sleep (standard deviation, SD, of sleep duration ≥1 hour) were randomized to Sleep Opt (n=5) or attention control (n=3) groups. Sleep Opt included use of a Fitbit, weekly digital content, interactive tools, and weekly coach delivered feedback, targeting insufficient and irregular sleep behavior. Sleep recording (7-day actigraphy) and continuous glucose monitoring (Abbott FreeStyle Libre®), questionnaires and A1C were performed at baseline and week 8. Results: Sleep duration and A1C improved in both groups (Sleep duration: Sleep Opt +7 minutes vs. control +25 minutes, A1C: Sleep Opt -0.085% vs. control -0.9%). Glycemic variability (CV%) and TIR improved in the Sleep-Opt vs. control group (%CV -3.2 vs. +0.32, TIR +7.0% vs. -5.7%) respectively. Sleep regularity (SD of midsleep time) improved in Sleep Opt vs. control group (-26 vs. +1 minute). Fatigue, depressed mood and diabetes distress had a greater improvement in Sleep Opt vs. control group. Conclusion: This pilot study provides preliminary evidence that the Sleep-Opt intervention improved sleep, glucose parameters and important patient-reported variables. Larger studies and more scalable intervention should be explored as means to improve sleep and glycemic control in T1D with inadequate or irregular sleep. Disclosure P. Martyn-Nemeth: None. S. Reutrakul: None. J. Duffecy: Consultant; Self; Kitchry Health. L.T. Quinn: None. A.D. Steffen: None. Funding Chicago Center for Diabetes Translation Research; National Institute of Diabetes and Digestive and Kidney Diseases (P30DK092949)