Left ventricular hypertrophy, especially concentric hypertrophy, has been shown to be an independent factor of cardiovascular diseases in patients with hypertension. Obstructive sleep apnea (OSA) and/or metabolic syndrome (MS) are common in patients with resistant hypertension (RHTN). The aim of this study was to evaluate factors associated with concentric hypertrophy in patients with RHTN. Data from 155 patients (92M, 63F) was analyzed. All patients underwent a thorough examination including: biochemical evaluations, ambulatory blood pressure monitoring, polysomnography and echocardiography. MS was defined by The Adult Treatment Panel III. Clinically significant OSA was defined as apnea/hypopnea index (AHI)>15 events per hour. Left ventricular mass index (LVMI) and relative wall thickness (RWT) were calculated. Four types of LV geometry were distinguished based on the LVMI and RWT. Patients were divided into four groups based on the LV geometric patterns: group 1 (normal geometry) (n=38, 24.4%); group 2 (concentric remodeling) (n=40, 25.8%); group 3 (eccentric hypertrophy) (n=26, 16.8%); and group 4 (concentric hypertrophy) (n=51, 33%). MS was found in 64% and OSA (AHI>15) in 43.2% of patients. Factors independently associated with concentric hypertrophy were: age (OR-1.51; 95% CI-1.00-2.27; P<0.04), OSA>15 events per hour (OR-2.73; 95% CI-1.26-5.93; P=0.01) and nighttime systolic blood pressure (SBP) (OR-1.69; 95% CI-1.32-2.17; P=0.0001). Concentric hypertrophy was the most common type of left ventricular disorder in patients with RHTN. Nighttime SBP and clinically significant OSA were independently associated with concentric hypertrophy in patients with RHTN.