Background: Although brachial-ankle pulse wave velocity (baPWV) is simple and convenient, its usefulness as an initial screening test for hypertensive patients is not well-known. This study aimed to investigate the association of baPWV with left ventricular (LV) geometry and diastolic function in treatment-naive hypertensive patients. Methods: A total of 202 untreated hypertensive patients (mean age, 62 years; males, 51.5%) without documented cardiovascular diseases were prospectively enrolled. Both baPWV and transthoracic echocardiography were performed on the same day before antihypertensive treatment. Results: In multiple linear regression analysis after adjustment for potential confounders, baPWV had significant correlations with structural measurements of LV including relative wall thickness (β = 0.219, P = 0.021) and LV mass index (β = 0.286, P = 0.002), and four diastolic parameters including septal e' velocity (β = -0.199, P = 0.018), E/e' (β = 0.373, P < 0.001), left atrial volume index (β = 0.334, P < 0.001), and maximal velocity of tricuspid regurgitation (β = 0.401, P < 0.001). The baPWV was significantly increased in patients with LV hypertrophy, abnormal LV remodeling, or diastolic dysfunction, compared to those without (P = 0.008, P = 0.035, and P < 0.001, respectively). In the receiver operating characteristic curve analysis, the discriminant ability of baPWV in predicting LV hypertrophy and diastolic dysfunction had an area under the curve of 0.646 (95% confidence interval 0.544-0.703, P = 0.004) and 0.734 (95% confidence interval 0.648-0.800, P < 0.001), respectively. Conclusion: baPWV was associated with parameters of LV remodeling and diastolic function in untreated hypertensive patients. The baPWV could be a useful screening tool for the early detection of adverse cardiac features among untreated hypertensive patients.