A system for measuring blood pressure of a user that comprises an ElectroCardioGram (ECG) circuit with at least two ECG electrodes configured to obtain an electrical activity of a heart of the user by measuring the electrical signals detected at the at least two ECG electrodes as an electrocardiogram waveform, and a pulse oximeter circuit configured to obtain a pulse waveform corresponding to a blood flow on user's vessels. The system further comprises a processor that is in electrical contact with the electrocardiogram circuit and the pulse oximeter circuit. The processor is configured to simultaneously analyze the electrocardiogram waveform and the pulse waveform. The processor is further configured to identify a “Zero Voltage Crossing” point on the electrocardiogram waveform and to determine time delays from this point to respective different determined points of the pulse waveform; and to use the time delays to compute the blood pressure values