Hypertension is the most important preventable risk factor for premature death worldwide. It can increase the risk of cerebral, cardiac, and renal events. Subtle target-organ damage such as left-ventricular hypertrophy, microalbuminuria, and cognitive dysfunction takes place early in the course of hypertensive cardiovascular disease while catastrophic events such as stroke, heart attack, renal failure, and dementia usually happen after long periods of uncontrolled hypertension only. Thus, primary prevention of hypertension may reduce the overall risk of cardiovascular diseases. Although hypertension is a multifactorial disease, autonomic nervous system (ANS) is an important factor in the development and prognosis of hypertension. Heart rate variability (HRV) has been used as a simple non-invasive technique to examine ANS. The aim of the study was to compare HRV of newly diagnosed essential hypertensive subjects with controls. The study was conducted on 120 hypertensive subjects and 120 controls. The time domain measures which reflect parasympathetic activity, standard deviation of all RR intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD), and percentage of consecutive RR intervals that differ by more than 50 ms (pNN50) were significantly less in hypertensive subjects. In frequency domain measures, high frequency [HF (ms2)] and HF (nu) which reflect parasympathetic activity were significantly less in hypertensive subjects while LF (nu) and LF/HF (%) which reflect sympathetic activity were comparable between the groups. These findings suggests that HRV is reduced in men and women with newly diagnosed essential hypertension and the parasympathetic dysregulation is present in the early stage.