Aim Our study aims to assess the prevalence of metabolic syndrome (MS) in patients with diabetes mellitus, identify its determinants, and determine the correlation between MS and degenerative complications. Method A retrospective, descriptive and analytic study was conducted at the Endocrinology, Diabetology, and Nutrition department of the Hassan II University Hospital in Fez, over the period between January 2009 and January 2019. We included in our study all type 1 and type 2 diabetic patients. The presence of metabolic syndrome was defined according to the criteria of the International Diabetes Federation (IDF) and American Heart Association/National Heart, Lung and Blood Institute (AHA / NHLBI) Joint Scientific Statement (2009). The data were entered in Microsoft Excel (Microsoft Corporation. 2018). and analyzed using SPSS software (IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp). Result A total of 1034 patients were included in this study; 78.7% were type 2 diabetics (T2D) and 21.3% were type 1 diabetics (T1D). The average age was 52,06 ± 17,33 years in T2D and 27,04 ± 9,66 years in T1D. 65,5% were females. The prevalence of metabolic syndrome was 78.4% for T2D, and 27.3% for T1D. The most common abnormality was high blood pressure in T2D (87.7%), and visceral obesity in T1D (68.3%). The most common triad was the association of increased waist circumference, hypertension, and diabetes (in 25,5% of T2D and 20% of T1D). By comparing the population of diabetics with metabolic syndrome (MS) and those without, we noticed a significant difference (p<0.05) concerning age, gender, all components of MS (high blood pressure, abdominal obesity, hyper triglyceridemia (TG), and hypo high-density lipoprotein cholesterol (HDL-C). Diabetic retinopathy and ischemic heart disease were the only chronic complications correlated with MS (p <0.05). Conclusion High prevalence of metabolic syndrome in diabetic patients. Its screening and the specific treatment of its various components are essential in order to reduce the complications which jeopardize the functional as well as the vital prognosis of these patients.