BACKGROUND There are many patients in society using antihypertensive medication, which has been initiated just after a single office measurement but actually they are normotensive and in contrast, there are many patients not using any antihypertensive medication because of a normal blood pressure (BP) at the doctor's office but they are actually hypertensive. METHODS We randomly took 438 consecutive patients. Clinical BP was measured by the same physician, and a 10-day twice daily home blood pressure measurement (HBPM) and 24-hour ambulatory blood pressure measurement (ABPM) were obtained. RESULTS Among 438 patients, 170 (38%) normotension (NT), 190 (43%) white coat hypertension (WCHT), 10 (2%) masked hypertension (MHT), and 68 (15%) sustained hypertension (HT) cases were detected. Although the prevalences of sustained HT and MHT increased by decade, the prevalence of WCHT was much higher in all decades until the eighth decade. Even in the second decade, its prevalence was 33% and higher than 45% in the third, fourth, and fifth decades of life. No statistically significant difference was found for number of WCHT, MHT, and sustained HT cases between ABPM and HBPMs. CONCLUSIONS HBPM should be the preferred method of diagnosis of WCHT, MHT, and sustained HT against conventional BPM at the doctor's office and even ABPM due to its simplicity and equal effectiveness with ABPM. It should be applied to every patient above the age of 40 years once a year due to high prevalences of sustained and masked HT cases. Additionally, due to the very high prevalences of WCHT even in the very early decades, WCHT should be thought of as a normal response of the body against various stresses and its management should be limited to annual follow-up with HBPMs.