Abstract: A fluid filter having a hollow, molded, plastic housing with an open end, a fluid inlet port and a fluid outlet. An internally threaded, plastic, molded cap is threadedly received on the housing via mating external threads for sealing the open end of the housing. A cap seal prevents fluid contamination of the threads. A removable filter element is contained within the housing between the fluid inlet and the fluid outlet. A molded, resilient, plastic retainer captured between the cap and the filter element retains the filter element in position within the filter. If the filter element is of a bag filter type, as compared with a filter cartridge type, the retainer has a plurality of resilient legs which press down upon a bag mouth seal forcing it into contact with a flared mouth of the bag support.