Background: The exaggerated blood pressure response to exercise (EBPR) is an independent predictor of hypertension. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide inhibitor and higher plasma levels of ADMA are related to increased cardiovascular risk. The aim of this study is to identify the relationship between ADMA and EBPR. Methods and Results: A total of 66 patients (36 with EBPR and 30 as controls) were enrolled in the study. EBPR is defined as blood pressure (BP) measurements >200/100 mmHg during the treadmill test. All the subjects underwent 24-h ambulatory BP monitoring. L-arginine and ADMA levels were measured using a high performance lipid chromatography technique. The serum ADMA levels were increased in the EBPR group compared to the healthy controls (4.0±1.4 vs 2.6±1.1 yumol/L respectively, P=0.001), but L-arginine levels were similar in the 2 groups (P=0.19). The serum ADMA levels were detected as an independent predictor of EBPR (odds ratio 2.28; 95% confidence interval 1.22-4.24; P=0.002). Conclusions: Serum ADMA levels might play a role in EBPR to exercise.