Objective: The new coronavirus disease (COVID-19) has spread rapidly all over the world and caused anxiety disorders. Recent studies have also shown that the prevalence of depression and anxiety increased during the COVID-19 outbreak. We aimed to evaluate the anxiety and depression levels during the pandemic and identify the effect of pandemic-related stress on blood pressure (BP) control in primary hypertensive patients. Method: A total of 142 patients with primary hypertension (HT) who continued to use the same antihypertensive drugs before and during the pandemic were included in the study. Twenty-four -hour Ambulatory Blood Pressure Monitoring (ABPM) and the Hospital Anxiety and Depression Scale (HADS) questionnaire were applied to patients. We retrospectively reviewed 24-h ABPM records of the same patients for the year before the pandemic. Results: Daytime, nighttime and 24 -hour-systolic blood pressure (SBP) levels as well as daytime, nighttime, and 24- hour-diastolic blood pressure (DBP) levels, were significantly elevated during the COVID-19 outbreak compared to the pre-pandemic period (p<0.001). Higher HADS-A scores (HADS-A ≥7) were significantly associated with much greater increase in BP compared to the patients with lower HADS-A scores. Conclusion: Psychological stress due to the COVID-19 outbreak led to worsening of the regulation of BP in controlled hypertensive patients whose antihypertensive treatments did not change.