The authors evaluated the association of Parkinson's disease (PD) duration with hypertension, assessed by office measurements and 24-hour (ambulatory) monitoring, in 167 patients. Hypertension was evaluated through both office and ambulatory blood pressure (BP) measurements. Among participants (mean age 73.4 +/- 7.6years; 35% women), the prevalence of hypertension was 60% and 69% according to office and ambulatory BP measurements, respectively (Cohen's k=0.61; P<.001). PD duration was inversely associated with hypertension as diagnosed by office measurements (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.86-0.98) but not by ambulatory monitoring (OR, 0.94; 95% CI, 0.81-1.01). Ambulatory BP patterns showed higher nocturnal BP among patients with long-lasting disease. In conclusion, ambulatory BP monitoring improves the detection of hypertension by 15% in PD, compared with office evaluation. The likelihood of having hypertension does not decrease during the PD course; rather, BP pattern shifts towards nocturnal hypertension.