Background: Type 2 diabetes mellitus (T2DM) is a global pandemic and its prevalence is rapidly increasing in developing countries, including Thailand. The most common comorbidity of T2DM is hypertension. T2DM with a hypertension comorbidity is likely to exacerbate the development of, or more severe microvascular complications. This study aims to determine the association between the hypertension comorbidity and microvascular complication among T2DM patients in Thailand. Methods: The present study is a nationwide, multicenter, cross-sectional survey of T2DM outpatients across Thailand. Binary logistic mixed effect regression was used to investigate the effect of hypertension and other risk factors on the presence of microvascular complications. Imputation was used to investigate potential bias introduced by missing values. Results: Of the 55,797 T2DM patients included in our sample, 55.35% were hypertensive. Prevalence of microvascular complication diagnosis in the last 12 months was higher in T2DM patients with hypertension than those without hypertension (12.12% vs. 9.80%, respectively). Patient with a hypertension comorbidity had 1.32 time the odds of developing microvascular complication (adjusted odds ratio [OR], 1.32; 95% confidence interval [CI], 1.20 to 1.46; P<0.001). Older age, longer diabetes duration had 1.07 and 1.21 times the odds of developing microvascular complication, per 10 years (age) and 5 years (duration), respectively (ORage, 1.07; 95% CI, 1.03 to 1.12; P<0.001; and ORduration, 1.12; 95% CI, 1.07 to 1.16; P<0.001; respectively). Minimal bias was introduced by missing values, and did not influence to the magnitude of effect of hypertension on the presence microvascular complication. Conclusion: Hypertension comorbidity is highly associated with microvascular complication among T2DM patients. Patients with T2DM and physicians should pay attention to blood pressure control.