The prevalence of glucose metabolism abnormalities in PCOS women worldwide varies between 10 and 40% but there are no data in Greek PCOS women. In this retrospective study the prevalence of glucose abnormalities and the indices of insulin resistance (IR) and whole-body insulin sensitivity were estimated in a Greek population with PCOS. Impaired glucose tolerance (IGT), impaired fasting glucose (IFG) and type 2 diabetes mellitus (t2DM) were calculated. The prevalence of IGT, IFG and t2DM in our PCOS population was 7.6, 5.1 and 1.7%, respectively. The total prevalence of glucose abnormalities was estimated as 14.1%. The prevalence of t2DM was three- to four-fold higher than in the general Greek female population of the same age as this was estimated by 2, recently published studies. PCOS women with increased BMI and waist circumference and age greater than 30 years, present more severe IR and decreased whole-body insulin sensitivity. Our data indicates a relatively high prevalence of glucose intolerance and t2DM in a Greek population with PCOS. Obese women with PCOS are in higher risk to develop glucose abnormalities and probably t2DM later in life and therefore every woman diagnosed with PCOS should undergo a 2-h post load OGTT.