BACKGROUND: Hypertension is a common disease and one of the most important risk of cardiovascular disease. Majority of patients with hypertension are unaware of their conditions until complications develop. Awareness of hypertension is important in treating and controlling of hypertension. Therefore, we conducted a study on the factors related to awareness of hypertension. METHODS: Awareness of hypertension was evaluated by measuring blood pressure(BP) in 3,344 subjects visiting a health promotion center in Pusan National University Hospital from June 1996 to May 1997. All subjects completed a questionnaire including socio-demographjc factors and family history. Hypertension was defined as systolic BP above 140mmHg and/or diastolic BP above 90mmHg. 135 subjects were diagnosed as hypertension. RESULTS: Among 315hypertensives, only 135 subjects(42.9%) were aware of their conditions. With respect to sex, women had a better awareness of hypertension than men(51.6% vs 36.9%, P<0.05). The awareness was greater for the subjects aged over 60years than for the subjects aged 30-49 years(53.3% vs36.5%), and it was statistically significant(P<0.05). The subjects with stage III hypertension had a better awareness of hypertension than the subjects with stage I(65.5% vs 32.6%, P<0.05) In the occupation-types, the awareness was highest in the group without occupations. But except the group without occupations(56.2%), the awareness was highest in the group of domestic affairs(housewives, 53.2%). Education level and monthly mean income were not related to awareness of hypertension. With respect to marital state, the rate of awareness is highest in the group of widows or widowers(55.8%, P<0.05). The subjects with family history of hypertension had a better awareness of hypertension than the subjects without(59.6% vs 35.7%, P<0.05). The rate of alcohol drinking(47.4% vs 66.7%), smoking(21.5% vs 31.6%) and high salt intake(17.0% vs 25.0%) were lower and the performance rate of regular exercise(24.4% vs 13.3%) was higher in those who were aware of their hypertensions than those who were not. CONCLUSIONS: The awareness of hypertension was also associated with sex, age, marital sate, occupation, stage of hypertension, family history of hypertension, and was related to performance of lifestyle modification (alcohol drinking, smoking, salt intake, exercise).