A liquid filter, especially for oil of an internal combustion engine, with a bypass valve including a valve body 20 and a valve seat 21 integrated in an end plate 32 of the filter insert. A spring 22, which urges the bypass valve closed, is mounted in a support member 24 attached to the housing. Thus, parts of the bypass valve subject to wear and soiling can be replaced each time filter element 18 is replaced, and reliable operation of the bypass valve is assured throughout the life of the filter. The filter insert can be designed free of metal for easy disposability. The filter cartridge can also be used with known filter arrangements in which a permanent valve body is housed in the support member 24. When the filter element of the invention is used, this permanent valve body stays in the support member and functions as an intermediate piece 35, which transmits force between spring 22 and valve body 20. The valve function is assumed by new valve body 20 engaging valve seat 21.