Elevated blood pressure (BP) is frequently diagnosed in very elderly hospitalized patients. Accurate diagnosis of hypertension is challenging in the hospital environment, due to the "white coat effect," and both overtreatment and undertreatment can adversely affect clinical outcome. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has the potential to avoid the "white coat effect" and accurately guide the management of hypertension. However, effects of the hospital environment on ABPM are unknown in the very elderly. We set out to enroll 45 patients, age ≥70 years, with elevated conventional BP during hospitalization in this observational study. It was prespecified by protocol to assess initially the difference between 24-hour BP during hospital-admission and home follow-up. Subsequent analysis should investigate the change in anxiety (Hospital Anxiety and Depression Scale-A [HADS-A]) after discharge, the correlation with change in 24-hour BP after discharge, and the prevalence of orthostatic hypertension. Thirty-one patients were included in the final analysis (age 83.5 ± 4.4 years; 71% female). Twenty-four-hour BP decreased significantly after hospital discharge (systolic from 133.5 ± 15.6 to 126.2 ± 14.4 mm Hg [millimeter of mercury], P = .008; diastolic from 71.0 ± 9.0 to 68.3 ± 8.6 mm Hg, P = .046). Anxiety level (HADS-A) decreased significantly after discharge, from 7.5 (interquartile range [IQR]: 4.0-13.8) to 5.0 (IQR: 4.0-8.0, P = .012). The change in anxiety was a predictor of change in systolic BP after discharge (F[1,20] = 5.9, P = .025). Sixty-one percent of the patients had significant orthostatic hypotension during hospital stay. In conclusion, 24-hour BP in very elderly patients is lower in the home environment than during hospitalization. This phenomenon seems to be directly linked to a lower anxiety-level at home. Reassessing hypertension at home may decrease the need for (intensified) antihypertensive medical therapy in a substantial number of patients. This is particularly important in the very elderly, who have a high prevalence of symptomatic and asymptomatic orthostatic hypotension, making them prone to hazardous effects of antihypertensive therapy.