A method and an apparatus for monitoring an operating state of at least one tire of a vehicle are provided. The monitored operating state may be, for example, the air pressure of the tire. One tire state variable that represents the current operating state of the tire, and one calibration variable that represents the target tire state of the tire, are taken into consideration in the monitoring. The monitoring is accomplished in different monitoring modes, i.e., the particular monitoring mode employed is determined as a function of at least one driving state variable representing the driving state. In an example embodiment, for a given driving state variable, the vehicle speed is selected as the differentiation criterion for the different monitoring modes.