The aim of this study was to assess the factors associated with impaired vascular function in patients with poorly controlled type 2 diabetes (DM2) with and without overt cardiovascular disease (CVD). Ninety-five patients with DM2 and poor glycemic control were recruited and divided into two groups: Group 1, with known CVD (n
= 38), and Group 2, without CVD (n
= 57). Patients in Group 2 were further subdivided into those with short (<5 years, group 2b) and long (>5 years, group 2a) diabetes duration. Subclinical markers of atherosclerosis were assessed. Glycemic control was similar in the two groups (HbA1c: 9.2% (1.5) vs. 9.4% (1.8), p
= 0.44). In Group 1, lower FMD (3.13 (2.16)% vs. 4.7 (3.4)%, p
< 0.05) and higher cIMT (1.09 (0.3) mm vs. 0.96 (0.2) mm, p
< 0.05) was seen compared with Group 2, whereas PWV was similar (12.1 (3.4) vs. 11.3 (3.0) m/s, p
= 0.10). Patients in Group 2b had significantly lower PWV and cIMT and higher FMD compared to Group 1 (p
< 0.05). Among patients with poorly controlled T2D, more pronounced vascular dysfunction was present in those with overt macrovascular disease. In patients with T2D without known CVD, vascular dysfunction was associated with disease duration. The use of vascular indices for cardiovascular risk stratification in patients with T2D requires further study.