In a method for automatic non-invasive monitoring of a patient's blood pressure, a cuff is applied around an arm of the patient and inflated to a predetermined pressure. Thereafter the pressure applied to said cuff is stepwise reduced. On the basis of the amplitudes or peak-to-peak values of the oscillations of the pressure signal measured at the individual pressure steps, a blood pressure value is derived. In order to be able to take arrhythmias into consideration in such a measurement method, oscillations that have been recognized to be artifact-free are sorted in accordance with various criteria, whereupon the frequency is determined with which the oscillations fulfill these criteria. Depending on the frequency with which the criteria are fulfilled, specific oscillations are selected whose mean value is utilized for determining the blood pressure.