Objectives: This study examines the awareness of hypertension and its age-specific characteristics among Korean adults. Methods: Data were derived from the fourth Korean National Health Examination and Nutrition Survey (KNHANES IV, 2007-2009) of 14,637 subjects aged 30 and older. Self-reported prevalence of hypertension (HTN) was compared with measured arterial systolic/diastolic blood pressure, employing Kappa index, sensitivity, and specificity. Multiple logistic regression analysis was used to determine factors in hypertension awareness by age groups. Results: Kappa agreement between self-reported and measured data in hypertension was high (0.70, 95% CI 0.68-0.71). Awareness by sensitivity was relatively high (65.3%) and specificity was very high (98.8%) for all ages. After age stratification, the results revealed the very lowest level of hypertension awareness among the youngest age group: 29.1% of adults aged 30-49 years, 57.5% of adults aged 45-59 years, and 76.9% of those aged ≥ 60 years. Predictors for awareness differed by age group. Among adults aged 30-49 years, men exhibited lower awareness to HTN than women. Among middle-aged adults, workers showed lower awareness than non-workers. Among those aged ≥ 60 years, men and the less educated showed lower awareness to HTN than their counterparts. Conclusions: Age-specific prevention strategies are needed for hypertension management.