Introduction: The American Heart Association/American College of Cardiology has published new guidelines for hypertension in 2017. These guidelines change the criteria to classify patients with hypertension. There has not yet been a study that analyzes the consequences of these changes in developing countries. The objective of our study was to characterize changes in the classification of hypertension with the new guidelines among Peruvian patients and to determine the factors associated with being newly diagnosed as hypertensive. Methods: An analytical cross-sectional investigation was carried out, which was based on the secondary analysis of the data of hypertension. We compared certain variables including using antihypertensive medication, region, and other sociodemographic characteristics. We performed a descriptive analysis of the variables shown as frequency and percentage. P values that were less than 0.05 were considered statistically significant, obtained using a multivariate analysis. Results: Of the 5,615 patients in this cohort, with the old criteria 4,915 (87.5%) did not have the diagnosis of hypertension; however, with the new criteria 1,415 (25%) will be diagnosed with hypertension. 467 (9%) of patients who were not taking medications and 85 (32%) of patients who were taking medications will switch from having high-normal blood pressure to grade 1 hypertension, with the new guideline. The recent diagnosis of hypertension was associated with sex (p <0.001), age (p <0.001), being overweight (p <0.001), physical activity (p = 0.010), smoking (p = 0.031), and a history of diabetes mellitus (p <0.001). When adjusted for pharmacotherapy, only sex (p <0.001), age (p <0.001), being overweight (p <0.001), and physical activity (p = 0.001) remained statistically significant. Conclusions: The new criteria increased the percentage of patients that now will be classified with hypertension. This should be accompanied by effective politics in education, surveillance, and adequate treatment of the health care system.