Introduction: Homocysteine ​​and concentration of Hcy serum test is the new problem has less been studied in Vietnam, especially in patients with hypertension. Objective: Determination of serum homocysteine ​​levels in patients with hypertension. Method: descriptive, cross-sectional in patients with hypertension treated in A Thai Nguyen hospital. Result: The mean Hcy concentrations in patients with hypertension was 19.30 ± 1.5 (μmol / l) was higher with statistical significance (p <0.05) compared with controls (10.23 ± 0.8 (μmol/l)); Hcy concentration increases with the degree of hypertension, higher male-female, infrequent treatment group and the treatment duration greater than 5 years of regular treatment group and the treatment duration of 5 years statistically significant (p <0.05). Conclusion: Hcy serum concentration is higher than the control group, increases with the degree of hypertension, gender and adherence in hypertensive patients.