As a modifiable risk factor for cardiovascular disease, presence of hypertension (HT) necessitates the awareness of asymptomatic organ damage (AOD). The aim of this study was to measure plasma micro RNA-21 (miR-21) and the parameters that reflect AOD such as carotid intima-media thickness (CIMT), microalbuminuria (MAU) in hypertensive patients compared with healthy controls. In addition, the aim of this study was to evaluate plasma miR-21 levels in HT patients with AOD.This study was designed as a cross-sectional observational study. The study includes 2 groups: 32 patients with HT and 32 healthy controls. First, we compared these 2 groups. Then, to underline the relationship between plasma miR-21 and HT, hypertensive patients were divided into 2 groups: with AOD and without AOD.Sixteen patients with HT had AOD. MiR-21 levels significantly correlated with clinical systolic and diastolic blood pressure, MAU, C-reactive protein, and CIMT. CIMT, miR-21, and MAU levels were significantly higher in patients with AOD.Our study showed increased miR-21 levels in HT patients with AOD.