The next generation fully implantable pressure sensors are valuable for intracranial pressure (ICP) monitoring, particularly in the chronic conditions of hydrocephalus. However, the accuracy, particularly in terms of the sensor drift over long duration, is a key concern. An implantable pressure monitoring system will rely on a flexible thin-film membrane as part of the pressure sensor and will interfere with a corrosive fluid (saline/blood) at a temperature of approximately 37 $$^\circ \hbox {C}$$ ∘ C . The physics of the underlying thin film (material aging, mechanical fatigue), independent of the surrounding medium, triggers drift in the long-term monitoring of ICP. Therefore, finite element modeling (FEM) of thin-film deflection and fatigue life are essential. Although the FEM provides a theoretical view of the underlying issue, it is also necessary to validate the accuracy of the model. In this paper, we present both the numerical modeling and experimental validation of thin-film deflection and fatigue life of thin film titanium foils. The salient feature of this work is the approach of the thin-film deflection and fatigue testing (as part of the entire sensor) in contrast to the standard dog-bone based fatigue testing.