The aim of this study was to establish a five-year cumulative incidence of arterial hypertension (hereinafter 5-CIAH) and its dependence on initial prehypertension, body weight, age and gender "Croatian Adult Health Cohort Study (CroHort)" data collected during 2003 and 2008 for the 1383 subjects aged 18 + with initially normal blood pressure (systolic < 140 mmHg and diastolic < 90 mmHg, and not taking medication) was analised. Methods of descriptive statistics, Student's t-test, chi2-test and logistic regression were used. The recorded 5-CIAH in male cohort was 36.9% [32.1 to 41.6] and 33.0% [30.1 to 36.0] in women and was higher in subjects with initial prehypertension (men 43.3% [37.5 to 49.0] versus 9.6% [12.1 to 27.2]; women (42 3% [38.1 to 46.6] versus 22.3% [18.5 to 26.1]). The development of arterial hypertension was affected by age (OR = 2.2168), initial prehypertension (OR = 2.1987) and overweight (OR = 1.9399).