A method and apparatus for diagnosis of liquid losses in pressure measuring transducers including a pressure sensor arranged in a pressure measuring chamber, and a pressure transfer structure connected to the pressure measuring chamber A sealed inner space of a separating diaphragm is composed of the inner spaces of the pressure transfer structure and the pressure measuring chamber and is filled with a pressure transmitting liquid, which, serves for transmitting pressure acting on the separating diaphragm to the pressure sensor. An apparatus for detecting liquid losses. The apparatus for detecting liquid losses includes a test element arranged in the sealed inner space. The outer volume of the test element is reducible for diagnosis of liquid losses. An evaluating unit, which serves, during diagnosis, for registering, as a function of a volume reduction of the test element, a pressure measured by the pressure sensor, and, on the basis of this pressure measured as a function of the volume reduction, for detecting whether liquid has escaped.