A humidifier with an integrated water separator for a fuel cell system, including a housing with a first channel for a first gas stream and a second channel for a second gas stream, a humidifier area in which the first channel and the second channel are separated from one another by a water vapor-permeable membrane, and a collection container for collecting the deposited liquid water is provided. It is provided that a water separator for separating liquid water is situated in the humidifier area.