The potential ability of unattended office blood pressure (AOBP) has been acknowledged worldwide, including Japan, although much resource consumption makes it less feasible to use AOBP in clinical practice. We reported that the three consecutive AOBP measurement values in each patient were almost identical, with high correlations (r ≥ 0.90), and the AOBP and conventional attended office blood pressure were moderate to highly correlated. We therefore interpret that AOBP can be an alternative that is more stable than the conventional attended blood pressure value despite with the average shifted to some extent, e.g., 10.4/4.2 mmHg based on the same study. In contrast, there is a fundamental discrepancy between the similarity in average values and the poor agreement in individuals when we compare AOBP versus self-measured home blood pressure, as the systolic blood pressure difference was 0.9 mmHg with a 95% agreement limit was -34.0 to + 35.8 mmHg. The vast wide range of difference indicates that we cannot estimate home as well as ambulatory blood pressure values by AOBP measurements in each patient, and vice versa. AOBP has another advantage regarding the elimination of white-coat effect by the presence of medical staff. Nevertheless, because AOBP measurement is performed at a clinic or in a screening setting where participants cannot be relaxed like at their own home, such a clinic effect still affects AOBP readings. In this session, the current evidence on AOBP based on our Japanese studies and others will be summarized and issues which remain to be investigated for the assessment of a variety of blood pressure conditions, unattended and attended office, and out-of-office blood pressures will be discussed.