Although the stimulating effect of thyroid hormones on energy metabolism has been known for about a century, the relationship between thyroid function, weight control, and obesity is unclear. Objective: Our work aims to bring a focus on the association between obesity and thyroid pathology. Methods: A descriptive and retrospective study of all obese patients who had consulted or been hospitalized in the Department of Endocrinology, Diabetology and Nutrition at University Hospital Center Hassan II in Fez, over a period of 2 years from January 2016 to December 2018. All patients with a BMI ≥ 30 kg / m2 were included. The data were plotted on a table in the Excel 2010 program and analyzed using the SPSS 18 program. Results: 150 patients met our criteria, their mean age was 45.26+/-12.77 years with a female predominance (sex-ratio = 1/25). 10.66 % of our patients had dysthyroidism; among them hypothyroidism was individualized in 56.25% of cases. In this category, the serum TSH concentrations were positively correlated with BMI (p=0.011) and a significant weight loss was objectified after the start of hormonal treatment. While hyperthyroidism was present in 43.75% of our patients, 57.14% had morbid obesity and the response to weight gain after radical treatment (iratherapy or surgery) was minimal. Conclusion: Obese patients may develop thyroid dysfunction and even thyroid dysfunction may contribute to the gradual increase in body weight, resulting in overt obesity.