BACKGROUND Obesity (OB) is a global pandemic, which is associated with arterial hypertension (AH). The differences in this relationship according to gender and age remain unclear. The objectives of this study were to establish the prevalence of OB and AH in an adult population, and to determine the risk of AH associated with OB in relationship to gender and age. METHODS A cross-sectional study was performed using the database of successive cross-sectional studies carried out in 5 city squares in Resistencia (Argentina) during the years 2008-2014. The sample was randomised according to gender and age, according to the distribution of the last National Argentine Census. RESULTS A total of 7,898 passers-by (46.8% males) with a mean age 42.74 ± 16.70 years were included. OB in men increased from 21.3% to 26.9%, and in women from 15.2% to 23%, the former having the highest prevalence between 40-49 years, and the latter between 50-59 years, and thereafter it was always higher in women. AH increased in men from 39.9% to 42.7%, and in women from 25.8% to 29.2%, the former having the highest prevalence between 60-69 years, the latter between 70-79 years. CONCLUSIONS In the 7 years of the study, OB and AH prevalence increased. It was higher in men, although the risk of developing AH associated with OB was greater in older women. The highest prevalence of OB and AH appears a decade earlier in men.