Objective. To investigate the impact of generalized anxiety disorder (GAD) on the circadian rhythm of blood pressure in patients with hypertension. Methods. The 24-h ambulatory blood pressure was compared between patients with hypertension and GAD, and patients with hypertension only. Results. The mean day- and night-time systolic (SBP, 156.611.0 and 149.612.4 mmHg, respectively) blood pressure in patients with GAD was greater than in the no-GAD group (143.215.0 and 126.010.8 mmHg, respectively, P0.01). The mean day- and night-time diastolic blood pressure (DBP, 101.510.1 and 96.917.6 mmHg, respectively) in the GAD group was also greater than in the no-GAD group (94.110.9 and 77.410.2 mmHg, respectively, P0.01). SBP and DBP dipping was found in 87.5 and 80.1% of the hypertension only patients, as compared with 16.6 and 21.4% respectively, of the hypertension and GAD patients (P0.01). Conclusions. The presence of GAD is associated with a higher level of blood pressure in hypertensive patients. GAD is also associated with a diminished circadian rhythm of blood pressure. The clinical significance of the reduced blood pressure dipping at night requires further investigation.