We sought to determine whether insulin resistance (IR) is related to arterial stiffness in nondiabetic hypertensive patients, independent of metabolic status and gender. IR has been associated with increased arterial stiffness in patients with diabetes. In nondiabetic hypertensive patients, the correlation between IR and arterial stiffness has yet to be investigated. We enrolled 284 nondiabetic patients who were being treated for hypertension. At the time of enrollment, the patients underwent a baseline laboratory assessment including homeostatic model assessment (HOMA) IR index and pulse wave velocity (PWV). The HOMA IR index is used as a marker of IR, and brachial to ankle PWV (baPWV) was used as a marker of arterial stiffness. Of the 284 study subjects, 121 were classified as having metabolic syndrome. The patients with metabolic syndrome were older than the non-metabolic syndrome patients (55.4+/-10.7 vs. 52.1+/-11.6 years, p=0.013), but there was no gender difference between the two groups. The average baPWV was significantly higher in the patients with metabolic syndrome (1,506+/-235 vs. 1,435+/-211 cm/s, p=0.009). The HOMA index was independently associated with an increase in arterial stiffness (r=0.548, p<0.001) after controlling for age, systolic blood pressure (SBP), heart rate, medication and gender. The independent association of HOMA with arterial stiffness was demonstrated in subgroup analysis, regardless of the metabolic status and gender. In conclusion, increased IR was associated with arterial stiffness, independent of age, baseline SBP, gender and heart rate. This independent association of IR was demonstrated regardless of gender and metabolic status.