Background: Evidence supports a causal relationship between circadian disturbance and impaired glucose homeostasis. Method: To determine the effect of a nursing educational intervention on improving healthy sleep, a parallel, open-label clinical trial in subjects with Impaired Fasting Glucose (IFG) or Type 2 Diabetes Mellitus (T2DM) and 18 and older was performed. Study variables were sex, age, fasting glucose, glycated hemoglobin A1c (HbA1c), Pittsburgh Sleep Quality Index (PSQI), sleep duration and efficiency, BMI, antidiabetic treatment and diet and physical exercise. An individual informative educational intervention was carried out following a bidirectional feedback method. It was intended to develop skills to improve sleep through 9 simple tips. An analysis of covariance was performed on all the mean centered outcome variables controlling for the respective baseline scores. Results: After the intervention, in the experimental group, PSQI dropped, the duration and quality of sleep increased. Further, a decrease in fasting glucose and in HbA1c levels was observed. Conclusion: The proposed intervention has proven to be effective to improve sleep quality, time, and efficiency and in only 3 months, to achieve a decrease in fasting glucose and HbA1c levels. These findings support the importance of sleep and circadian rhythms education focused on improving in T2DM or IFG.