Abstract: A dual filter system for diesel fuel is provided, which allows the operator to keep the diesel engine running while inspecting or replacing one of the two fuel filters. The system includes an upper block which is divided into two identical mirror image sections. Each section has a shutoff valve, a fuel filter and a one-way check valve. Fuel is introduced into a common passageway and flows equally to each side of the upper block. Fuel is fed through each filter and filtered fuel moves through the one-way check valve to a common outport. In order to inspect or replace one filter, the fuel to the filter to be replaced is simply, shut off by the cutoff valve. All of the fuel then flows through the opposite side. The one-way check valves prevent fuel flowing through the opposite side from flowing back into the side which is being serviced. Air bleed valves are also provided in order to put the new filter side back in operation.