Blood pressure (BP) is the main biomarker for monitoring patients, as its lack of control above values considered normal is a modifiable risk factor for target organ damage. The aim of this study is to evaluate the accuracy of the wearable electronic device photoplethysmography technology (PPG) Samsung Galaxy Watch 4 in determining BP in young patients compared to manual and automatic methods of BP determination. This is a quantitative and cross-sectional study, following validation protocols for wearable devices and BP measurement. It was carried out with twenty healthy young adults, in which BP was measured using four instruments, namely, standard sphygmomanometer device (manual), automatic arm oscillometric device (reference), wrist oscillometric device, and Smartwatch PPG. Eighty systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings were observed. SBP means manual 118 ± 2.20,arm 113 ± 2.54, wrist 118 ± 2.51, and PPG (smartwatch) 113 ± 2.58. Among means, arm and PPG difference is 0.15, arm and wrist 4.95, arm and manual 4.45 wrist with PPG. The mean DBP manual 76.7 ± 1.84, arm 73.6 ± 1.92, wrist 79.3 ± 1.87, and PPG 72.2 ± 1.38. Among means, the difference between the arm and PPG is 1.4 and arm and hand 3.5 mmHg. The correlation shows PPG with manual, arm, and wrist. There was a strong SBP correlation and a moderate DBP correlation between the methods tested, evidencing the accuracy of the PPG smartwatch in relation to the reference method.