Prehypertension is a clinical condition that increases the risk of hypertension and cardiovascular disease. In South American countries, prehypertension affects almost one-third of the population. The aim of the present study was to determine the association between prehypertension and the main cardiometabolic risk factors according to the US National Cholesterol Education Program Adult Treatment Panel III by sex in the Peruvian population. A total of 863 participants surveyed were included in the study. A total of 21.1% had prehypertension, 14.4% of whom were female, and 30.5% were male. Women belonging to the age group 50–59 years, having abdominal obesity and being a current smoker, were more likely to have prehypertension, while the likelihood of having prehypertension increased in men with abdominal obesity. Three out of 10 men and one out of 10 women in Peru have prehypertension. In women, being 50 to 59 years of age, having abdominal obesity, and being a current smoker, increased the probability of having prehypertension, whereas, in men, only abdominal obesity was found to be associated with prehypertension. Our findings will allow the development of prevention strategies focused on the appropriate diagnosis of prehypertension and cardiometabolic risk factors according to sex.