It has been suggested that metabolic syndrome (MetS) overlaps prediabetes and type 2 diabetes and that it is not necessary to consider it as a separate clinical entity. In the present study, patients with normoglycemia and dysglycemia were compared in terms of MetS frequency and MetS criteria characteristics, in order to test the appropriateness of considering MetS as a condition independent of prediabetes and type 2 diabetes. A total of 1222 (801 females, 401 males, mean age: 51.50 11.73 y) consecutive patients attending Internal Medicine outpatient clinics were included. Cases were assigned into two groups: patients with normoglycemia (fasting plasma glucose <100 mg/dl, n = 555) or dysglycemia (fasting plasma glucose >/=100 mg/dl and/or receiving antidiabetic treatment, n = 667). Groups were compared in terms of MetS frequency and MetS criteria characteristics. A 2-hour oral glucose tolerance test was administered to the normoglycemia group. In addition, patients with MetS were assigned into two groups: patients with normoglycemia and dysglycemia. These two groups were also compared in terms of MetS criteria characteristics. Adult Treatment Panel III criteria were used for the diagnosis of MetS. The overall frequency of MetS was 52.2%. MetS was found in 72.7% of patients with dysglycemia and 27.6% of patients with normoglycemia (p = 0.001). Mean systolic and diastolic blood pressure, waist circumference and triglyceride levels were similar between normoglycemic and dysglycemic MetS patients (p>0.05). Impaired glucose tolerance was higher among normoglycemic MetS patients compared to normoglycemic patients without MetS (13.7% vs. 6.5%, p = 0.006). In conclusion, although MetS is a well known risk factor for type 2 diabetes, our results support that it is a separate entity independent of prediabetes and type 2 diabetes mellitus.