The present study aims to investigate the excessive daytime sleepiness in patients with hypothyroidism and in the healthy control group using the Epworth sleepiness scale. Methods: This study was completed with 127 people, 75 of whom were hypothyroidism and 52 were control group. Age, height, weight, body mass index, waist circumference, systolic and diastolic blood pressure of the all participants were recorded. Thyroid hormone tests and biochemical parameters were examined in the morning. Epworth Sleepiness Scale was used to measure daytime sleepiness. Results: Epworth Sleepiness Scale scores were 7.3±0.7 in the hypothyroid group and 6.4±0.4 in the control group, and there was no significant difference between the groups (p=0.703). Weight (p<0.001), body mass index (p<0.001), waist circumference (p=0.001) and triglyceride levels (p=0.001) were higher and high density lipoprotein levels were lower (p=0.001) in the hypothyroid group than the control group. Total cholesterol, low density lipoprotein level and high density lipoprotein level were lower in patients with hypothyroidism and excessive daytime sleepiness than those without hypothyroidism. High density lipoprotein levels were also lower in the group with normal thyroid function and excessive daytime sleepiness. There was no correlation between Epworth Sleepiness Scale scores and age, weight, height, body mass index, waist circumference, neck circumference, thyroidstimulating hormone, systolic and diastolic blood pressure and blood lipid levels (p>0.05). Conclusion: Hypothyroidism and control group were similar concerning excessive daytime sleepiness. However, metabolic parameters deteriorated in daytime sleepy group compared to non-daytime sleepy group. It was concluded that similar studies with broader participation should be conducted.