This study investigates the association between the allelic distribution of two polymorphisms of the angiotensinogen (AGT) gene (T174M and M235T in the polypeptide chain) and blood pressure (BP) in a Mediterranean population in the south-west of Europe. The sample consists of 1322 participants from urban and rural areas, from the province of Albacete (218,462 inhabitants), located in the south-east of Spain. The subsample of this study, adjusted by age (over 18 years old) and sex, consists of 401 individuals. A case-control study is conducted which analyses 205 individuals from the group with the highest BP (fifth quintile) and 196 from the group with the lowest BP (first quintile). In addition, a comparative and associated analysis of these polymorphisms with BP level and family history of hypertension is carried out. The T174 allele proved to be more common in the fifth quintile group, although not statistically so. When the presence of threonine was analysed in both polymorphism positions (174 and 235), the TTTT genotype was found to be more common in the fifth quintile than in the first quintile. Moreover, the TTTT genotype was significantly more common in individuals with a family history of hypertension, indicating that it could be considered a predisposing factor to high BP in individuals from such families. In addition, the T174M-T235T genotype was more common in the first quintile group, and showed significant association (P=0.05) with the group that had no family history of hypertension.