Objective:Few studies, using countrywide data, examined how hypertension prevalence varies at diverse degrees of urbanization and altitude. This study examined the association between urbanization and altitude, including the potential interaction between those variables, with hypertension prevalence in Peru.Methods:Cross-sectional analysis of the Peruvian Demographic and Health Survey (2014-2019). Hypertension (SBP ≥140mmHg or DBP ≥90mmHg or self-reported diagnosis) was the outcome. Exposures were altitude levels, and urbanization assessed with four indicators (urban/rural; type of place of residence; population density level; and population size level).Results:Among 186906 participants (mean age ± standard deviation: 40.6 ± 17.9; 51.1% women), pooled hypertension prevalence was 19% [95% confidence interval (CI) 18.7-19.3], which was higher in urban compared with rural areas (prevalence ratio: 1.09; 95% CI 1.05-1.15). Compared with countryside, hypertension was higher in towns (prevalence ratio: 1.09; 95% CI 1.04-1.15), small cities (prevalence ratio: 1.07; 95% CI 1.02-1.13) and large cities (prevalence ratio: 1.19; 95% CI 1.12-1.27). Compared with least density settings (1-500inhabitants/km2), hypertension was higher in the highest density (≥10001inhabitants/km2) settings (prevalence ratio: 1.12; 95% CI 1.07-1.18). Population size was not associated with hypertension. Compared with low altitude, hypertension was lower above 2500m (prevalence ratio 0.91; 95% CI 0.87-0.94) and above 3500m (prevalence ratio 0.89; 95% CI 0.84-0.95). Interaction between exposures had varying patterning.Conclusion:Hypertension in Peru is more prevalent at urban than rural areas, especially in large cities and in more densely populated areas above 10001inhabitants/km2, and less prevalent at altitudes above 2500m.