Objective. Wide pulse pressure (PP) affects the accuracy of oscillometric blood pressure measurements (OBPM): however, the degree of this impact on different patient groups with wide PPs is unclear. This study will investigate the accuracy of OBPM in achieving target BP and PP in isolated systolic hypertension (ISH) group compared with mixed hypertension (MHT) group. Method. A total of 115 patients (70 with ISH and 45 with MHT) were enrolled in the study. Upper arm and wrist OBPM, obtained by OmronM3 and OmronR6 devices respectively, were compared with the simultaneously measured values from the ascending aorta. The ISH was defined as a systolic blood pressure (SBP) ≥140 mmHg and a diastolic blood pressure (DBP) <90 mmHg. MHT was defined as a SBP≥140 mmHg and a DBP≥90 mmHg. Results. The mean central arterial blood pressure (BP) and central PP were higher in the ISH group than those in the MHT group. The upper arm OBPM underestimated the central SBP in two groups (-5 mmHg, -3 mmHg, p=0.5, respectively), but overestimated DBP in the ISH group compared with MHT patients (6.8 mmHg, 1 mmHg, p=0.04, respectively). Wrist OBPM similarly underestimated to the central SBP in each group (-16 mmHg, -19 mmHg, p=0.15), whereas the sum of overestimation of DBP was significantly higher in the ISH than in the MHT group (+6 mmHg, - 1 mmHg, p=0.001, respectively). Also, each of the devices underestimated the central PP in the ISH group (about 10 mmHg) as being higher than that of the MHT group. Conclusion. Oscillometric devices may be used for self-BP measurement in patients with ISH without clinically important disadvantages compared with the patients with MHT. For PP measurement in patients with ISH, there were substantial differences between intra-arterial and indirect arm BP measurements. © Informa UK Ltd.