We aimed to evaluate the effects of non-dipper BP pattern on left ventricular (LV) rotational mechanics in hypertensive patients with type 2 diabetes mellitus (T2DM) with the utility of two-dimensional speckle tracking echocardiography (2D-STE). Eighty-six hypertensive patients with T2DM were enrolled. All patients underwent 2D-echocardiography and 24-h-ambulatory blood pressure monitoring. Fifty-nine (59.3%) patients had non-dipper BP pattern and all subjects had normal LV function. Patients with non-dipper BP pattern had decreased systolic tissue velocity (p: 0.006), increased peak systolic apical rotation and rotation rate (p: 0.008 and p: 0.014, respectively), and peak LV twist and twist rate (p: 0.005 and p: 0.012, respectively). Analysis of LV diastolic parameters showed that, early diastolic tissue velocity (Em) was decreased and E/Em ratio and LV mass (LVM) index were increased in non-dipper group while the time to LV untwisting rate was delayed. In multivariate analysis, peak LV twist (β = 0.459, p: < 0.001) and twist rate (β = 0.388, p: 0.001) were independently associated with the difference between mean arterial pressure (MAP)-asleep and MAP-awake. In correlation analysis adjusted for age, sex and LVM index, the time to LV untwisting rate was positively correlated with the difference between MAP-asleep and MAP-awake (r: 0.290 vs. p: 0.008) and E/Em ratio (r: 0.280 vs. p: 0.010). LV rotational mechanics are impaired in T2DM non-dipper hypertensive patients, indicating LV systolic and diastolic dysfunction. 2D-STE may permit better understanding of the underlying pathophysiology and development of preventive strategies.