We conceived new oscillometric blood pressure (BP) estimation methods based on physical modeling. The crux of these methods is to simultaneously estimate the arterial stiffness and BP of the patient from a standard oscillometric waveform. Hence, in contrast to previous methods, the BP estimation is specific to the patient at the time of measurement and is robust against arterial stiffening. We conducted initial testing of one of the methods against invasive reference brachial BP measurements in eight cardiac catheterization patients before and after nitroglycerin infusions. The method achieved systolic, diastolic and mean BP root-mean-squared-errors of 7.2, 7.6 and 6.7 mmHg. These errors were, on average, 40% lower than an existing high-end method.