Arterial stiffness interacts with hypertension, becoming an early marker of hypertension-mediated target organ damage. This study aimed to assess the association between plasma concentrations of bone morphogenetic protein-4 (BMP-4) and arterial stiffness during hypertension.Using cardio-ankle vascular index (CAVI) to determine arterial stiffness status, 204 individuals with essential hypertension were classified into two groups, high CAVI (abnormal) group (n = 94) and low (normal) CAVI group (n = 110). Data were collected including clinical characteristics and laboratory measurements. Plasma levels of BMP-4 were tested by using ELISA analysis.Plasma levels of BMP-4 were substantially greater in high CAVI group than that in low CAVI group [38.51 (31.79-50.83) pg/mL vs. 31.15 (29.38-32.37) pg/mL; p < 0.001]. As shown by spearman correlation analysis, BMP-4 concentrations were correlated with CAVI values in hypertensive individuals (r = 0.406, p < 0.001). After adjustment for potential confounders, elevated BMP-4 levels were related with high CAVI (OR, 1.070; 95% CI, 1.003-1.108; p < 0.001). The best BMP-4 cutoff value for identifying high CAVI, as determined by ROC curve analysis, was 33.34 pg/mL (AUC, 0.751; 95% CI, 0.683-0.818; p < 0.001).Plasma levels of BMP-4 are increased in hypertensive individuals with high CAVI. Elevated BMP-4 levels are strongly correlated with higher CAVI values, implying a predictive value of BMP-4 in arterial stiffness during hypertension.© 2022 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.